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LEATHER MANUFACTURE 

A PRACTICAL HANDBOOK 



TANNING, CURRYING, AND CHROME 
LEATHER DRESSING 



By ALEXANDER WATT 

AUTHOR OF "THE ART OF SOAP-MAKING," " ELECTRO-METALLURGY," ETC., ETC. 



FIFTH EDITION, THOROUGHLY REVISED AND ENLARGED 



NEW YOEK 

D. VAN NOSTRAND COMPANY 

23 MURRAY AND 27 WARREN STREETS 
LONDON 

CROSBY LOCKWOOD AND SON 

1906 



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PEEFACE. 



The Author deems it advisable, in explanation of the 
appearance of the present volume, to mention that, not- 
withstanding diligent inquiry, he was unsuccessful in 
meeting with an English work on the subjects com- 
prised therein. It is true there are articles upon Leather 
Manufacture in our various scientific cyclopgedias and 
technical journals, but to the Author's mind it appeared 
strange that so important an art should be unrepre- 
sented by a special work upon the subject in this 
country, while other countries, especially Trance, Ger- 
many, and Austria, have provided numerous books upon 
the various branches of the trade. 

It therefore seemed to the Author that a carefully pre- 
pared Handbook, embodying all the information he could 
gather which seemed likely to be useful to the various 
trades concerned, and including recent processes and im- 
provements, could not fail to prove widely acceptable to 
manufacturers and others interested in the art. He con- 
sequently set to work to construct such a book, with the 
result which is now in the reader's hands. 

In referring to the numerous sources of information 



iv PREFACE. 

upon the subject, the Author was much surprised at the 
vast store of useful knowledge which was Avidely diffused 
through a considerable number of works and periodicals 
not directly addressed to the trade, much of which would 
probably never come within view of those for whom it 
was written. To these, and the several trade journals — 
The Leather Trades' Circular, The Tanners? and Curriers* 
Journal, and The Scottish Leather Trader — he gratefully 
acknowledges his indebtedness ; as also to the several 
works referred to throughout the volume. 

Soon after having determined to undertake the present 
work, the Author put himself in communication with 
several manufacturers, requesting permission to have a 
general view of their works, and to those who kindly 
acceded to his request he now returns his warmest thanks, 
but more especially to Messrs. Bevingtons & Sons, the 
eminent tanners of Bermondsey, and to Messrs. Carlaw 
Brothers, for the generous spirit in which they ex- 
plained to him the various processes of manufacture 
conducted at their establishments. He has also to thank 
Mr. Sparke Evans, of the Avonside Tannery, Bristol, for 
many useful suggestions. 

In conclusion, the Author indulges a hope that his effort 
to supply an evident want in English technical litera- 
ture, may meet with the approval of his readers, and that 
the book will prove useful for reference to everyone con- 
nected with the art. 



PUBLISHEES' NOTE TO THE 
FIFTH EDITION. 



Since the issue (in 1897) of the Fourth edition of this 
work, as revised by the late Mr. Alexander Watt, rapid 
strides have been made in the Leather industry. In fact, 
so great and constant, it appears, are the advances now 
being made, that it is all but impossible to keep abreast 
of them in a technical Handbook. The Publishers felt 
assured, however, that much of the data here collated 
and prepared by Mr. Watt was far too valuable to be 
cast aside, and having, after that gentleman's death, 
received inquiries from all parts of the world as to when 
a revised edition would be available, they felt themselves 
fortunate to be able to engage the services of a well- 
known expert who was prepared (within the limits 
arranged) to thoroughly revise the work, and make 
such additions as should bring it up to date. This was 
by no means an easy task, but it is believed that the 
Keviser (while retaining such parts of Mr. Watt's work 
as were of permanent value) has succeeded in giving, 
also in a condensed and easily digestible form, a sum- 
mary of most of the modern methods now pursued 
by Tanners and Leather Manufacturers. Several of the 



VI PUBLISHERS' NOTE TO THE FIFTH EDITION. 

original chapters, dealing with older-fashioned leathers 
which have practically passed out of use, have been 
omitted, their place being taken by descriptions of 
tanning and dressing the more modern leathers, such 
as chrome, calf, and goat skins. In some cases, the 
space available would not allow him to do more than 
give the bare technical outlines of the processes in- 
volved ; and in others the Reviser has had to assume a 
certain amount of knowledge on the part of the reader. 

A brief description has been added of the " Standard " 
method of tannin estimation, but the scientific reader 
who requires fuller information on this important sub- 
ject is referred to Prof. H. E. Procter's " Leather Indus- 
tries Laboratory Book," where he will find full justice 
done to the Chemistry of Leather Manufacture. The 
illustrations of machinery (it will be found) have been 
brought up to date, but it will not be forgotten that 
so rapid is the progress made by the Tanner's Engineer 
that new ideas for appliances are of almost daily occur- 
rence. The introduction of the Chrome process of leather 
manufacture was a golden opportunity for mechanical 
enterprise, of which British, American, and Continental 
engineers have not been slow to avail themselves, and 
they are reaping a rich harvest in catering for the wants 
of the Tanner. 

It is right to mention that the technical methods 
described in the work are such as have stood the test 
of practical experience, and although some of them may 
have to be modified to suit individual special or local 
requirements, yet it is certain that students of the sub- 
ject will obtain much that is of real value from an 
intelligent perusal of what is here written. The recipes 



PUBLISHERS' NOTE TO THE FIFTH EDITION, vit 

given are not only actual working ibrmiike, but many 
of them have been hitherto regarded as trade secrets. 

In conclusion, the Publishers may be allowed to 
quote the words of the Reviser, who has reminded them 
that " in the Manufacture of Leather competition is 
becoming keener year by year, and the cost of manual 
labour is making it almost prohibitive for many pur- 
poses. ' The old order changeth, giving place to the new,' 
but it is not without a pang of regret that even the most 
enterprising man sees the old forms of ancient skilled 
trades swept aside by the march of progress. However, 
this seems to be one of the inevitable trading conditions 
of the twentieth century. The day is over when profit 
could be made easily and quickly in the leather trade, 
and it is only by close study of economy in the manu- 
facture, and careful organisation for the disposal of the 
product, that progress can be made. In pursuing the 
former of these two courses, close study, both of the 
science and of the practice of the Leather industry, is 
essential ; and if what he has written and compiled in 
preparing the present edition is a help in that direction, 
the Reviser will feel that in his attempt to bring the work 
of the late Mr. Watt into line with modern methods 
he will have accomplished a most useful service for the 
followers of a most interesting calling." 



CONTENTS. 



TACE 

Intkoduction ...1 



CHAPTEE I. 

CHEMICAL THEORY OF THE TANNING FXOCESS. 

Properties of Gelatine — Action of Tannic Acid on Gelatine, &c. — 

Seguin's Theory of the Art of Tanning 11 

CHAPTEE II. 

THE SKIN. 

The Skin — Structure of the Skin — Mr. Ashe's Description of the Skin 

— Composition of the Skin 23 

CHAPTEE III. 

HIDES AND SKINS. 

Classification of the Skins of Animals — Condition of Hides and Skins 
— Hides — Native Hides — Dried Hides — Salted Hides — Dried 
Salted Hides— Selection of Hides — Warbles — Abusive Treatment 
of Raw Hides — Kips— Buffalo Hides — norse Hides — Ass and 
Mule Hides — Hippopotamus Hides — Calves' Skins — Sheep Skins 
— Lamb Skins — Goat Skins — Kid Skins — Hog and Pig Skins — 
Seal Skins — Deer Skins — Porpoise Skins — Serpent and Croco- 
dile Skins 28 



X CONTENTS. 

CHAPTER IV. 

TANNIN OR TANNIC ACID. 

TAGB 

Tannin or Tannic Acid — Preparation of Tannic Acid — Pelouze's Pro- 
cess — Berzelius' Process — Bouillon-Legranee's Process — Merat- 
Guillot's Process — Dize"s Process — Deyeux's Process — Proust's 
Process — Serturner's Process — Schering's Process — Badvil and 
Lienders' Process — MM. Coez's Process — Kohlrausck's Process 
— Properties of Tannic Acid — Parnell's Views — Pure Tannic 
Acid — EeactioDs of Tannic Acid — Table of the Percentage of 
Tannin in Vegetable Substances — Morfit's Observations — 
Artificial Tannin ......... 43 



CHAPTER V. 

GALLIC ACID. 

Gallic Acid — Preparation of Gallic Acid from Galls — Scheele's 
Method — Liebig's Method — Graham's Method — Pharmaceutical 
Methods — Properties of Gallic Acid — Pyrogallic Acid — Ellagic 
Acid 57 



CHAPTER VI. 

GALLIC FERMENTATION. 
Checking or Preventing Gallic Fermentation . . . .63 

CHAPTER VII. 

TANNING MATERIALS. 

Sources of Tannin — Barks — Oak Bark — Barking of Trees — Nut 
Galls — Tanning Extracts — Catechu — Kino — Gambier or Terra 
Japonica — Hemlock Extract — Chestnut Extract — Oakwood Ex- 
tract — Larch Extract — Quebracho Extract — Sumac — Bhatany 
Boot — Mmigrove Extract — Myrobalans — Valonia — Divi divi — 
Mimosa Bark — List of Tanning Materials — Miscellaneous Tan- 
niDg Materials . . . . . . . .68 



CONTENTS. XI 

CH APT ETC VIII. 

ESTIMATION OF TANNIN. 

PAGE 

Examination of Bark — Determination by Specific Gravity — The 
Barkometer — Chemical Methods of Estimating Tannin — Davy's 
Method — Bell Stephens' Method — Hammer's Method — Lowen- 
thal's Method— Mr. Hewitt on Lowenthal's Method — Mr. Procter 
on Lowenthal's Method — Rainspacker's Method — The Tanno- 
meter — Casali's Process — -Standard Method — International Asso- 
ciation of Leather Trades' Chemists . . . . .88 

CHAPTER IX. 

PRELIMINARY OPERATIONS. 

Treatment of Green or Fresh Hides — Method of Salting Hides — 
Cleansing the Raw Hides — Dried Hides — Softening Dried Hides 
— Brain's Process — Dry Salted Hides— Wet Salted Hides — 
Schultz's Views on the Treatment of Hides .... 108 

CHAPTER X. 

DEPILATION OR UN HAIRING SKINS AND HIDES. 

Depilation by Lime — Properties of Lime — Storing the Lime — Liming 
— Single Pit Method — Working in Rounds — Continental Method 
of Liming — Supposed Disadvantages of the Lime Process — Dr. 
Davy on the Action of Lime on Animal Matter — Working on the 
Beam — Rounding the Pelts — Depilation by Sweating — Cold 
Sweating — Depilation by Acids — Depilation by Saccharine 
Matter — Depilation by Caustic Soda— Depilation by Bisulphide 
of Calcium — Depilation by Charcoal — Depilation by Sulphide 
of Sodium— Palmer's Process — Beck's Process — The Pullman- 
Payne Process ......... 115 

CHAPTER XI. 

RAISING OR SWELLING. 

Raising— Bating— The Bate, or Grainer— The Pure— Scudding— 
Sulphuric Acid Bate — Turnbull's Process — Warrington's Process 
— Bating with Barley-meal— Lactic Acid for Bating — Formic 
Acid for Bating 138 



Xli CONTENTS. 

CHAPTER XII 

TANNING BUTTS FOR SOLE LEATHER. 

PAGE 

Bark Tanning — Old Methods of Tanning — -Modern System of Tanning 
— Preparation of ihe Ooze — The Leaches — The Handlers— The 
Layers — Mixed Tannages — Tanning by Suspension — The Sus- 
penders — Scouring — Drying the Tanned Butts — Old American 
Method — The Drying Loft — American Turret Drier — Working 
of the Turret Drier — Influence of Light upon Leather — Striking 
— Rolling the Leather — To determine when Leather is Tanned 
throughout .......... 143 

CHAPTER XIII. 

TANNING PROCESSES. 

The First English Patents for Tanning— Newton's Tanning Process 
— Aldricu's Process — Orgereau's Process — Jennings's Process — ■ 
Ballatschano and Trenk's Process — Lomas's Process — Michel, 
Kollen, and Hertzog's Process — Keasley's Process . . .109 

CHAPTER XIV. 

TANNING PROCESSES— (continued). 

Page's Process — Casimir Bez and Sons' Process — Snyder's Process — 
De Bock's Process — Funcke's Process — Hamer's Process — Cox's 
Process — Nossiter's Process — Desmond's Process — Burbidge's 
Process — Kleman's Process ....... 191 

CHAPTER XV. 

TANNING EY PRESSURE. 

Spilsbury's Process — Drake's Process — Knowly's and Ducsbury's 
Process — Fryer, Watt, and Holmes's Process — Mouren's Process 206 

CHAPTER XVI. 

QUICK TANNING. 

Quick Tanning — Dr. Ure's Views — Dussauce's Observations — Dietz'e 
Process — Needham's Process — Nuessly's Process — Bell's Process 
— Baron's Process — Another Quick Process — Guiot's Process — 
Danish Quick Process . . . . . . . .211 



CONTENTS. Xlll 

CHAPTER XVII. 

HARNESS LEATHER TANNING. 

PAGE 

Harness and Upper Leather — Crop Leather ..... 223 
CHAPTER XVIII. 

AMERICAN TANNING. 

Cold Sweating of Hides — Sweat Pits — Treatment of Hides in the 
Sw^at Pits — Treatment of Hides after Sweating — Liming — Un- 
hairing by Prof. Lupkin's Process — Beam Work — Trimming or 
Rounding — Grinding the Bark — Leaching — The " Press " Leach 
— Raising with Vitriol — Handling — The Rocker Handler — The 
Layers 228 

CHAPTER XIX. 

HEMLOCK TANNING. 

Pratt's System of Tanning — Hemlock Tanning of New Lebanon — 

Hibberd's Process 245 

CHAPTER XX. 

TANNING EY ELECTRICITY. 

Ward's Process — Gaulard's Process — Gaulard's Second Process — 
Merit en's Process — Crosse's Process ..... 254 

CHAPTER XXI. 

CHEMICAL TANNING. 

Knapp's Processes— Heinzerling's Chrome Process — Heinzerling's 

Second Chrome Process — Vanderstraaten's Process . . . 260 

CHAPTER XXII. 

MISCELLANEOUS PROCESSES. 

Indian Method of Prepariug Elk-skins — Old Irish Process of Tanning 
— Tanning Nets, Sails, and Cordage — Glycerine in Tanning — 
Bleaching Leather . 268 



XIV ' CONTENTS. 

CHAPTEE XXIII. 

PAGE 

ON THE COST OF AMERICAN TANNING . . 272 

CHAPTER XXIV. 

MANUFACTURE OF LIGHT LEATHERS. 

Russia Leather — Count Kartstoff's Description of Russia Leather 
Manufacture — Smoking Skins — Another Method of Preparing 
Russia Leather — Black Russia Leather — Yufts Russia Leather 
— Morocco Leather — Sumac Tanning — Imitation Morocco 
Leather — Skiver — Cordovan Leather — Roan — Hungary Leather 
— Wallachia Leather — Barley Dressing — Morfit's Remarks on 
"White Dressing — Red Dressing — Bran Dressing — Enamelled 
Leather .......... 276 

CHAPTEE XXV. 

DYEING LEATHER. 

Dyeing Morocco Leather — Dyeing with Aniline Colours — Dyeing 
Kid Leather for Boots — Bath Dyeing — Dyeing on a Flat Surface 
— Aniline Colours in Glove Dyeing — DyeiDg with Pure Aniline 
Colours 299 

CHAPTER XXVI. 

MANUFACTURE OF WHITE LEATHER. 

Tawing as Distinguished from Tanning — TawiDg Operations — Kid 
Leather : Treatment of Kid Skins — French Kid Leather — 
Imitation Kid — Continental Method of Preparing Glove Leather 
— Calf Kid for Uppers — -White Sheep Leather — Splitting Sheep 
Skins 306 

CHAPTER XXVII. 

CHROME LEATHER MANUFACTURE. 

Preliminary Operations —Liming and Unhairing — Fleshing — Puring 
or Deliming — Scudding — Chroming Operations — Striking-out 
and Shaving — Dyeing Chrome Leather — Fat Liquoring — Dye- 
ing Black — Putting or Striking-out — Oiling and Drying — 
Staking or Softening —Seasoning — Glazing .... 323 



CONTENTS. XV 

CHAPTER XXYIH. 

BOX-CALF MANUFACTURE. 

TAGE 

Striking-out and Shaving— Fat Liquoring— Dyeing Black— Finish- 
ing Operations . • • • ■ • ■ • • <™-° 

CHAPTER XXIX. 

CHAMOIS, OR OIL-LEATHER MANUFACTURE. 
Preparation and Frizing— Drenching— Stocking or Milling in Oil- 
Pressing and Washing— Finishing — Chamois Glove Leather — 
Bleaching— Tucking— Colouring— Buff Leather— Liming— Pre- 
paring and Milling— Scudding and Wash-house— Buck Skin 
Dressing— Milling or Stocking— Scudding and Wash-house . 357 

CHAPTER XXX. 

CURRYING. 

The Scouring-house— The Shop— The Curriers' Knife — Currying 
Kip Leathers — Waxed Kip Butts — Sorting and Pounding — 
Soaking and Softening — Re-tanning — Drum-stuffing — Setting — 
Finishing — Stoning and Starching — Graining — Waxing— Top- 
sizing — Currying Satin or Glove Shoe Leather — Soaking and 
Splitting — Buffing— Blacking and Setting — Finishing Satin or 
Glove Leather— Levant Leather — Soaking and Splitting — 
Setting, Buffing, and Embossing — Black — Seasoning and Glaz- 
ing — Oiling — Currying Various Leathers — Wax Calf Skins — 
Calf Skins for Memel — High Shoes, Black Grain— Split Cow- 
hides for Brown Bags — Blocking Boot-fronts .... 368 

CHAPTER XXXI. 

MACHINERY EMPLOYED IN LEATHER MANUFACTURE. 

" Stocking " or Softening Machines— Dcpilxtion and Fleshing Plant 
— Machines for Crushing and Grinding Tanning Materials — Sole 
Leather Finishing Machinery — Leather Dressing Machinery — 
Scouring and Setting Machinery — Embossing and Softening 
Machinery — Tanning and Stuffing Drums — '■ Boarding " and 
Softening Machines — Machinery used in Chrome Leather 
Manufacture— Machinery used in the Beam House— Finishing 
Machinery for Chrome Work ...... 399 



XVI CONTENTS. 

( 

CHAPTER XXXII. 

EMBOSSING LEATHER. 

PAGE 

Copying Crocodile, Alligator, &c, Si ins ..... 431 
CHAPTER XXXIII. 

FELLMONGERING. 
Classification of Sheep Skins— Treatment of the Skins . . . 434 

CHAPTER XXXIV. 

PARCHMENT, VELLUM, AND SHAGREEN. 

Preparation of Parchment and Vellum — Skins for Drumheads— Sha- 
green — Fish Skin, or Fish Shagreen 437 

CHAPTER XXXV. 

GUT-DRESSING. 

Preparation of Cattle Intestines : Continental Method — Goldbeaters' 
Skin— Lathe Cords — Cords from Sheep Intestines— Cords for 
Tennis Bats, &c. — Whipcords — Gut Strings for Musical Instru- 
ments ........... 441 

CHAPTER XXXVI. 

GLUE-BOILING. 

Treatment of Glue-pieces, &c. — French Glue — Parchment Glue- 
Size— Glue Waste . . . 449 

CHAPTER XXXVII. 

UTILISATION OF TANNERS' WASTE. 

Spent Tan — Guest and Court's Process— Hide and Skin Cuttings — 

Hair Waste — Lime Waste- Glucose in Leather . . . 455 

Index 462 



EEEATA IN TEXT. 

Page vi., line 5, for ' chrome, calf ' read ' chrome calf.' 
,, xi., ,, 6, for ' Mr. Procter ' read ' Prof. Procter.' 
,, xi., ,, 8, for 'Standard Methods — International Association' 
read ' Standard Method of the International Asso- 
ciation.' 
,, xi., ,, 29 (Chapter Heading), for ' Raising or Swelling ' read 'De- 
liming or Bating.' 
,, xv., ,, 21, for ' Black ' read ' Blacking.' 
,, xv., ,, 29, for ' Leather Dressing Machinery' read ' Shaving and 

Splitting Machinery.' 
,, 88, ,, 6, for 'Mr. Procter ' read ' Prof. Procter.' 
,, 88, ,, 8, for ' Standard Method.— International Association ' 
read 'Standard Method of the International Asso- 
ciation.' 
138-142 (Chapter Heading), for ' Raising or Swelling ' read ' De- 
liming or Bating.' 
Page 399, line 6, for ' Leather Dressing Machinery ' read ' Shaving and 
Splitting Machinery.' 



Watt's ' Leather Manufacture. 



THE AET 

OF 

LEATHER MANUFACTURE. 



INTRODUCTION. 

In future ages the past century will ever be famous, 
not only for its important discoveries and useful inven- 
tions, but it will also be marked as an era in which, 
however tardily at first, the teachings of Science were 
accepted, and many useful arts rescued from empiricism 
and ignorance. Even within the memory of many now 
living, the innovations of Science were formerly looked 
upon with suspicion, as being not only unnecessary but 
possibly fraught with mischief. What could chemists 
know about soap-making, or of the art of tanning hides ? 
If good soap and good leather could be produced for so 
many generations without the aid of Science, why not 
continue in the same track as of old ? Reflections such 
as these inspired the workers in these arts for a long time 
after they were proved to be based upon definite chemical 
laws ; and it is well known that a deaf ear was turned to 
those who ventured to assert, and even to prove, that 
chemistry was indissolubly allied to those arts which had, 
from time immemorial, been conducted chiefly by the 
judgment of uneducated workmen. 

Although it must be confessed that the discovery of the 
chemical principles involved in the art of tanning has not, 
in its application, improved the quality of leather, still this 
important knowledge has enabled the tanner to work 
with greater economy and certainty, while Chemical 
Science has furnished him with an abundance of tanning 
materials of which, without such aid, he would doubt- 
less have remained in ignorance. Moreover, various 

B 



2 LEATHER MANUFACTURE. 

methods of quickening the process of tanning have been 
introduced which, in their turn, have facilitated the pro- 
duction of leather to meet the ever-increasing demand for 
this valuable article of universal, requirement. 

Respecting the early history of tanning, some very 
interesting facts are given in the Gerber Courier of 
Vienna, from which we extract the following : — " The 
oldest method of tanning is red or bark tanning, or that 
in which, in addition to the wooden and iron scraping and 
rubbing instrument used in the preparation or improve- 
ment of the hide or skin, limewater and astringent 
extracts from oak and other kinds of bark, or from other 
vegetable substances, are employed. It is called red 
tanning because the tanning substances always contain 
more or less colouring matter, which dye the leather 
through and through of a more or less reddish colour. 
The ancient Orientals understood the art of preparing not 
only common leather, but even good and often finely 
coloured varieties, similar to our Morocco and Cordovan. 
Persian and Babylonian leather has been celebrated time 
out of mind. Many centuries back such leather was 
brought from Asia into Europe — first into Turkey, Prussia, 
and Hungary, and thence, later, into Germany, Holland, 
England, France, Spain, &c, and these countries subse- 
quently learned to manufacture leather themselves. In 
the first centuries of Christianity, the Turks, Russians, and 
Hungarians were the most celebrated tanners ; subse- 
quently England, the Netherlands, and Spain endeavoured 
to equal them. 

"Among five sorts of leather of foreign origin, Cor- 
dovan, Morocco, Shagrin, and Russian leather have at all 
times been specially famous. Cordovan, a soft, small- 
grained, coloured leather, had already been prepared by 
the ancient Orientals. Its name is derived from the 
Spanish city of Cordova, whence it was possibly first 
introduced into Europe, and where, for a long time after- 
wards, it was chiefly manufactured. It enjoyed a great 
reputation in the eleventh century, when the most dis- 
tinguished persons wore shoes of Cordovan leather. The 



INTRODUCTION. 3 

French name for shoemaker, ' cordonnier,' appears also 
to have been derived from this leather. From the gradual 
improvement of Cordovan, sprang Morocco, called also 
Turkish and Spanish leather. This beautifully coloured 
and brilliant leather has always been most excellently 
manufactured in Morocco, in European and Asiatic Turkey, 
in KrimTartary, in the Island of Cyprus, &c, and very 
well also in Russia, Poland, Hungary, and Spain, but 
especially in England, France, Holland, and Germany. 

" Shag-rill (in Turkish Sagri, and Persian Sagre) is 
chiefly celebrated for its hardness and strength, and for 
the peculiarity of its grain side, which appears as if 
covered with globular granules. It is also of Eastern 
origin. The best Shagrin is now made in Persia, Con- 
stantinople, Algiers, and Tripoli. The production of the 
small globular granules on the grain side was for a long 
time kept secret. We were first informed by the cele- 
brated traveller, Pallas, that they were produced by 
stamping the hard seeds of the wild orach ( Chenopodium 
allium) into the hide spread on the ground. The 
seeds were afterwards knocked out, and the hide scraped 
on the indented side and soaked in water for two days. 
The Hungarians were, in ancient times, especially cele- 
brated for their white tanned leather, which was imitated 
in France as long ago as three hundred years. 

"We beg our readers to go back some centuries in 
history, and they will be convinced that the products of 
our trade were known in the time of Moses ; for at that 
period leather carpets were already used in tents. These 
we may still meet with among the Arabs. Coloured 
leather seems also to have been common, for Ezekiel 
speaks of fine red leather, which was probably our 
splendid red Morocco. Leather was also used in the 
remotest ages by the Israelites as a material to write 
upon, for they used strips made of leather for this pur- 
pose. According to the testimony of Herodotus, the 
ancient Ismians wrote their annals upon sheepskin, and 
the ancient Persians likewise, according to Diodorus of 
Sicily. According to Herodotus, the ancient Libyans 



4 LEATHER MANUFACTURE. 

wore leather clothing ; the Ichthyophagists on the banks 
of the Araxes dressed themselves in sealskins; and in 
the time of Alexander the wild inhabitants of Geodrosia 
used the hides of animals for clothing, and covered their 
dwellings with leather. Homer praises the splendid half- 
boots of Agamemnon, and Hesiod recommends leather 
shoes lined with fur. For many years leather was used 
by the Greeks in the construction of ships, especially by 
the Phoenicians, who originally inhabited an arid, sandy 
corner of the earth between the Red Sea and the Mediter- 
ranean, where the soil was not favourable to the growth of 
timber, and they were obliged to supply its place by 
covering their boats, constructed of willows woven to- 
gether, with leather or hides, which, even thus early, 
were subjected to a certain amount of dressing. The 
ancient Germans also, who lived on the sea-coast, and 
the original Britons, equally possessed this custom. 

"It is asserted that the art of dressing leather in 
general, upon the so-called Hungarian method, was first 
brought from Senegal, in Africa, and made known to us 
in the middle of the sixteenth century by Buscher, the 
son of a tanner in Paris. At that time leather was com- 
mon in Hungary, and dressed leather was very highly 
esteemed. In the year 1584 two German tanners, named 
Lasmagne and Aurand, came to Neufchatel, in Lorraine, 
where they worked at their trade ; from thence they went 
to St. Deziers, in Champagne, and finally to Paris, where 
they prepared very good leather. The theory that the 
preparation or tanning of the hides was discovered cen- 
turies ago, and that the leather produced was employed 
for the same purposes as at present, is further confirmed 
by the following old proverb, which is proof that leather 
shoes were already worn at that time : ' We must not 
steal leather to give away shoes in God's name.' This 
refers to the legend of St. Crispin, who stole leather to 
make shoes out of it for the poor. In the old form of 
speech, ' to draw from the leather ' signified to draw the 
sword. In low Saxon the same expression signifies to 
undress." 



INTRODUCTION. 5 

Although, the preceding observations indicate that the 
writer believed that the art of converting skins and hides 
into leather was not only exceedingly ancient, but also 
widely diffused, it is equally probable — except among the 
early Egyptians,* who must have known a comparatively 
high state of civilisation — that the so-called leather was 
in reality the skin or hide of the slaughtered animal 
merely dried in the sun or smoke-cured, and not what we 
understand by the term leather. Indeed it is well known 
that untanned skins have from all time been used by un- 
civilised tribes (as is also the case at the present time) for 
clothing and many other purposes. In some parts of 
France, even at the present day, bottles are made from 
skins of animals sewn up, and are used for the conveyance 
of wine and oil. The skins of animals were also used for 
making vessels to contain liquids — even wine ; but it is 
more than probable that the skins were merely dried in 
the sun and then externally greased to render them pliant 
and preserve them from the effects of moisture, or were 
cured by smoking, and not tanned in the ordinary sense. 
In support of this view, David, in Psalm cxix. 83, says, 
" I am become like a bottle in the smoke," which would 
indicate that the (skin) bottles in his time were cured by 
smoking. The preservative effects of the volatile matters 
given off by burnt wood were doubtless known at the 
earliest periods, and it is therefore reasonable to infer that 
the Psalmist alluded to this mode of preserving bottles 
made from the skins of smaller animals. Again, in the 
preceding verse, David says, "Mine eyes fail for thy 
word ; " may not this, taken in conjunction with his sub- 
sequent complaint, indicate that his vision, being impaired, 
caused him to behold objects as through a mist — " like a 
bottle in the smoke." Job, in chap. xxx. 30, says, " My 
skin is black upon me, and my bones are burnt with heat," 

* In the Egyptian collection of the British Museum may he seen a 
leather workman's apron, with a small purse-shaped pocket at the right 
side ; leather shoes with round toes, ankle and fore straps, most of them 
for children ; also other shoes of coarser and stouter make, and sandals of 
various forms and sizes ; shoes with high peaked toes ; rolls of prepared 
leather of a maroon colour, a yoke with one leather strap remaining, &c. 



6 LEATHER MANUFACTURE. 

probably also comparing bis lamentable condition to that 
of a bottle being cured by the smoke from burnt wood. 
Our Saviour refers to tbe necessity of putting new wine 
into new bottles, "else the new wine doth burst the bottles." 
Assuming that such bottles were made from the skins of 
animals, it is obvious that in course of time, through long 
use, they would become 'perished, as it is termed, and in 
such a brittle condition as to render them incapable of 
withstanding the pressure of new wine. 

In ancient writings the words skin and leather are evi- 
dently synonymous, but probably refer to the dried or 
cured skin. Kennett, in his Antiquities of Rome, speak- 
ing of the shoes, slippers, &c, worn by the ancient Romans, 
eays, "The perones were a kind of high shoes, rudely 
formed of raw hides, and reaching up to the middle of the 

leg Dacier tells us that the senators had two 

sorts of shoes, one for summer and the other for winter. 
The winter shoes were made of an entire black skin, or 
sometimes a white one, reaching up to cover the greater 
part of the leg, without any open place except at the top. 
.... It is uncertain whether the calcei mullei (red 
shoes) were so called from the colour of the mullet, or 
whether they lent a name to that fish from their reddish 
dye. They were at first the peculiar wear of the Alban 

kings, afterwards of the kings of Rome Julius 

Caesar, who was very singular in his whole habit, was 
particularly remarkable for wearing mullei on ordinary 

days The Roman solece were a sort of sandals, 

without any upper leather, so that they covered only the 
sole of the foot, being fastened above with straps and 
buckles. These were the ordinary fashion of the women, 

and therefore counted scandalous in the other sex 

The crepicla had two soles, whereas the solece consisted 
but of one. The former word is supposed to be derived 
from crepitus, creaking, from the peculiar sound which 
the double soles produced. Momus, when brought to 
censure Venus, could find no fault in her except that her 
slippers creaked a little too much ! " The Romans appear 
to have acquired a knowledge of leather manufacture at a 



INTRODUCTION. 7 

later period, and to have pursued it with great success. It 
is said that boots and shoes equal to those of the present 
age were worn by Roman ladies, and Pliny alludes to hides 
being tanned with bark, and also states that gall nuts, 
sumach, and lotus bark were employed in tanning. 

About 1300 A.D., embossed leather of great beauty was 
produced, specimens of which, in the form of tapestry, are 
still preserved in some of our old English mansions. 
Spain, Italy, Flanders, and England were famous for the 
production of embossed leather richly coloured and gilt. 
This"art having also been practised by the early Egyptians 
nearly three thousand years ago, it is probable that the 
countries above named may have revived and improved 
upon the Egyptian art. 

It was not until the end of the eighteenth century, and 
the commencement of the nineteenth, that the subject of 
tanning received the attention of scientific men, and the 
great result of their investigations was that the 'principles 
of the process of tanning were fully developed, and the 
chemical action of the tanning agents upon the pelt, or un- 
haired skin, definitely determined. The researches of 
Lewis, Deyeux, Seguin, Macbride, Prevost, and Sir 
Humphry Davy established the fact that the process of 
tanning was a chemical art, and as such should be con- 
ducted with a due amount of scientific method. But many 
years elapsed — nearly half a century, indeed — before 
tanners would recognise any suggested improvement. 

Up to about seventy years ago the tanners were men of 
small means, diffused throughout the country, unaided by 
railway communication and the advantages of machinery, 
while being utterly free from any knowledge of chemical 
principles. As a contrast to this condition of the trade, 
we have now an accumulation of extensive tanneries, 
many of which are situated near the great ports where 
the raw materials are landed from abroad ; and the 
capital invested in these establishments runs into 
several millions. In some of these the principles of 
the art are not only understood but more or less 
generally followed, while the advantages of labour-saving 



8 LEATHER MANUFACTURE. 

machinery have been recognised, and mechanical appli- 
ances adopted which the tanners of old would have looked 
at but to condemn. 

As the principles of tanning became better understood, 
many attempts were made to hasten the tardy conversion 
of skins into leather, some of which, emanating from 
practical tanners, being not only ingenious, but possessing 
the merit of being of a fairly practical nature. The first 
of these processes was due to Francis Spilsbury, who, in 
1823, took out a patent for a process by which the tanning 
liquor was forced through the skins by hydrostatic pres- 
sure. A modification of this process was introduced by 
William Drake in 1831, which consisted in having two 
skins sewn together, forming a watertight bag, in which 
the tanning liquor was introduced by means of a funnel ; 
the bag being thus filled, was kept constantly in this con- 
dition until the tanning was complete. In 1826, Messrs. 
Knowlys and Duesbury procured a patent for hastening 
the impregnation of the skins with tanning liquor by sus- 
pending them in a close vessel, from which the air could 
be exhausted by means of an air-pump. By this method 
the skins were said to be so effectually impregnated with 
tannin that their conversion into leather was greatly 
accelerated. 

Many other mechanical contrivances have from time to 
time been introduced, with a view to promote the rapid and 
uniform absorption of tannin by the skins, amongst which 
may be mentioned Nossiter's plan of separating the skins, 
while in the tan liquor, by wooden frames or partitions ; 
Keasley's arrangement for raising and lowering the skins 
alternately during the tanning operation, as a substitute 
for "handling;" and, more recently, Bez and Sons' 
method of tanning hides by means of a continuous flow or 
current of tanning liquor. These and other processes will 
be described in the subsequent pages. 

Since the period when Davy examined the chief tannin- 
yielding plants known in his time, a vast number of vege- 
tables have contributed to the tanner's list of tanning 
materials, some of which, employed either alone or mixed 



INTRODUCTION. 9 

with other sources of tannin, have proved highly service- 
able in the production of leather. Amongst these may be 
mentioned hemlock, valonia, mimosa, divi divi, myroba- 
lans, quebracho, &c. The foremost of these — hemlock — 
is the chief tanning agent of the Northern States of 
America, in which it abounds in unlimited profusion. 
Oakwood and chestnut extract is also largely imported 
into this country from Canada and the Continent. 

Many methods have been devised for the estimation of 
tannin, but the system proposed by Lowenthal, and sonie- 
whatTniodified by our own chemists, is now generally ac- 
cepted as the most reliable. While the simpler methods 
of determining the percentage of tannin, by the amount of 
gelatine required for its precipitation, or by the amount of 
tannin which a given weight of dried skin absorbs, will 
afford an approximate estimate of the proportion of tannin 
in a sample of bark or other tannin material, Lowenthal's 
method is capable of giving far closer and more reliable 
results than any other at present known.* 

Expatiating on the importance and extent of the leather 
manufacture in this country, Dr. Campbell says : " If we 
look abroad, on the instruments of husbandry, on the im- 
plements used in most mechanical trades, on the structure 
of a multitude of engines and machines ; or if we contem- 
plate at home the necessary parts of our clothing — shoes, 
boots, and gloves — or the furniture of our houses, the 
books on our shelves, the harness of our horses, and even 
the substance of our carriages, what do we see but in- 
stances of human industry exerted upon leather ! What 
an aptitude has this single material, in a variety of circum- 
stances, for the relief of our necessities and supplying 
conveniences in every state and stage of life ! Without 
it, or even without it in the plenty we have it, to what 
difficulties should we be exposed ! 

* Since the above was written, the " Standard Method," as adopted 
by the International Association of Leather Trade Chemists, is now 
generally used by European chemists for tannin estimation. A con- 
densed description of this is given at the end of chap. viii. p. 104. — Ed. 
Fifth Edition. 



io INTRODUCTION. 

While, in the early part of the past century, the 
soaprnaker was constantly under the surveillance of the 
exciseman, the tanner was equally favoured by the con- 
stant presence of that official supervisor ; at the soap- 
works, the coppers were locked and unlocked night and 
morning by the exciseman, while at the tanyard not a 
single hide could be shifted without his supervision, and 
in the case of any breach of the excise laws heavy penalties 
were inflicted. In the year 1830 the leather tax was 
abolished, and as evidence of the great impetus which this 
caused to the trade, in the year 1828 the value of exports 
of leather and saddlery were, collectively, £183,361, while 
in 1882 these exports'amounted to £2,348,242. 

Since that date, British trade in leather and leather 
goods has shown continued expansion. In 1905, leather 
to the value of £2,112,823 was exported, boots and 
shoes £1,882,294, and saddlery and harness to the value 
of £518,082. This, it must be remembered too, has 
been done in the face of ever-increasing hostile tariffs, 
for even the Australian Commonwealth has so raised the 
import duties, that it now only pays to send the finest 
classes of leather goods to the Antipodes. 



CHAPTER I. 
CHEMICAL THEORY OF THE TANNING PROCESS. 

Properties of Gelatine. — Action of Tannic Acid on Gelatine, &c 
Seguin's Theory of the Art of Tanning. 

The process of tanning consists in the conversion of the 
skins of animals into leather, by chemically combining 
with the substance of the skin an astringent vegetable 
principle called tannin, or tannic acid; and in order to 
thoroughly understand why this conversion takes place 
when skins are immersed in a solution of the tanning 
principle, we must know something of the chemical com- 
position of the skin itself. When the cuticle, or scarf 
skin, has been removed from the cutis, or true skin, it is 
found that the latter is almost entirely soluble when boiled 
in water, and the solution, after evaporation and cooling, 
sets into a jelly — this is gelatine, a substance which 
readily combines with tannic acid. Gelatine is also 
obtained in the same way from bones, cartilages, ten- 
dons, and ligaments. The purest form of gelatine is 
isinglass, prepared from the air-bladders and sounds of the 
sturgeon. 

Properties of Gelatine. — Pure gelatine is colourless, 
without odour, insipid to the taste, and transparent ; it is 
more or less tough, according to the source from which it 
is obtained. It is heavier than water, and when heated, 
it first becomes soft, and then shrinks. When burned, it 
exhales an odour resembling that of burnt horn. In cold 
water gelatine softens and swells, but only partially dis- 
solves; with gentle heat, however, it dissolves freely. 
Good glue, immersed in cold water, absorbs about three or 
four times its own weight of that liquid without dissolving. 




12 LEATHER MANUFACTURE. 

One part of isinglass dissolved in 100 parts of water, gela- 
tinises on cooling ; but in 150 parts of water it remains 
liquid; the gelatinising of the solution, however, will 
naturally depend upon the temperature of the atmosphere 
and the quality of the gelatine. The skins and tissues of 
the older animals yield a firmer jelly than those from 
younger ones. According to Brande, when a solution of 
gelatine is repeatedly warmed and cooled, more especially 
if it be boiled, it gradually loses its tendency to gelatinise, 
and becomes more and more soluble. In close vessels 
jelly may be kept in cool weather for some days without 
change ; but in open vessels it soon becomes mouldy, 
especially in the vicinity of flowering plants. " Gelatine 
is not soluble in absolute alcohol, and when alcohol is 
added to a warm and strong aqueous solution, the gelatine 
separates in the form of a white viscid substance. It is 
insoluble in ether, and in fixed and volatile oils. "When 
common gelatine, glue for instance, is digested in alcohol, 
it yields a little fat and extractive matter to that solvent. 
When jelly is immersed in alcohol, it contracts very con- 
siderably in consequence of the abstraction of water ; it 
was thus that Gonner applied it for the reduction in size 
of the impression of lithographic prints ; and, on the other 
hand, when the original impression was taken upon con- 
tracted gelatine, it could be so dilated by immersion in 
water, as to give a greatly enlarged impression of a small 
print. ' ' — Brande* 

Gelatine is soluble in all dilute acids, in which respect 
it differs from albumen. When treated with sulphuric 
acid, leucine and gelatine sugar are formed, the latter sub- 
stance having been discovered by Braconnot. One part 
of pulverised glue was mixed with two parts of concentrated 
sulphuric acid ; after having been left in this condition 
for twenty-four hours, during which time no discoloration 
took place, eight parts of water were added, and the mix- 
ture boiled for five hours, the water being renewed 
occasionally. The liquor was then further diluted, and 
saturated with chalk, then filtered and evaporated, when 
* " Manual of Chemistry." By William Thomas Brande, F.R.S., &c. 



CHEMICAL THEORY OF THE TANNING PROCESS. 13 

it yielded a syrup which, at the end of a month, produced 
small sweet crystals. These were afterwards washed with 
weak alcohol to separate the adhering syrup, and purified 
by a second crystallisation. Gelatine sugar requires 414 
parts of water to dissolve it. 

Action of Tannic Acid on Gelatine, &c. — The most 
delicate test for the presence of gelatine is tannic acid, 
and when we consider that a cloudy precipitate is produced 
by this vegetable acid in a solution consisting of 1 part 
gelatine in 5,000 parts of water, we may begin to 
realise its powerful influence upon the skin of animals in 
the process of tanning. When a piece of prepared skin — 
that is skin which has been soaked in milk of lime and 
freed from its cuticle, hair and other extraneous matters 
— is immersed in a solution of pure tannin (tannic acid) or 
an infusion of any astringent vegetable containing tannin, 
such as oak bark or gall nuts, and allowed to remain 
therein for a moderate length of time, the whole of the 
tannin combines with the skin, which becomes hardened 
and insoluble in water, and is absolutely incapable of 
putrefaction. It is, in fact, leather, and is almost impene- 
trable to water. 

The characteristic properties of tannin are astringency 
in taste, and the power of being precipitated from its 
aqueous solution by a persalt of iron, either of a bluish- 
black, or a dark green colour. The colour of the pre- 
cipitate, formed in a solution of tannin by persalts of 
iron, has been made the basis of an arrangement of the 
different tannins into two varieties, distinguished as 1, 
•tannin which precipitates iron bluish-black, and 2, tannin 
which precipitates iron green. Upon this subject Gfmelin 



" On the validity of the distinction between iron blueing 
and iron greening tannin, several views have been put for- 
ward, in which, however, these denominations have been 
understood as applying to two groups of bodies. If, 
according to Geiger, water containing a small quantity of 
alkali be gradually added to a ferric salt [as persulphate 
of iron], which has been turned green by any kind of iron 



14 LEATHER MANUFACTURE. 

greening tannin, the green colour changes to violet-black, 
the tint usually produced by iron blueing tannin. On 
adding an acid, the green colour is restored. According 
to this result, the difference between the two groups might 
be that the iron blueing tannin is less rich in free acid ; 
nevertheless, it reddens litmus more strongly than the 
other kinds of tannin. It appears to contain [_qy. to be 
capable of yielding] a larger proportion of gallic acid, 
but iron blueing tannin is not converted into the iron 
greening kind by the addition of gallic acid (Gmelin). 
The blue or green reaction is by no means an infallible 
characteristic of the species of tannic acid, since bases 
colour the ferric compounds of tannic acid blue, and 
acids change the blue to green. With ferric acetate, 
the iron greening acids form a blue compound ; the green 
compound which they form with other ferric salts is 
turned blue by the addition of a sufficient quantity of 
acetate of lead, either neutral or basic, and even by a 
large quantity of gelatine. A compound of iron greening 
tannic acid with lead oxide, is turned blue by ferric sul- 
phate (persulphate of iron) ; an iron greening tannic acid 
is turned blue by exposure to the air, in contact with iron 
turnings. But the colours obtained with iron greening 
tannic acids are very different from those produced by the 
iron blueing acids, and the two cannot be converted one 
into the other. 

"Thus, catechu-tannic acid (obtained by exhausting 
catechu with a small quantity of water), left in contact 
for a few days with iron filings, assumes a dirty- greyish, 
not a blue-black colour, and the precipitate does not turn 
green- when treated with a small quantity of acetic acid, 
but dissolves on the addition of a larger quantity, and is 
precipitated a purple-grey on the addition of ammonia. 
The iron greening tannic acids of catechu, kino, alder, 
larch, and birch bark, and of tormentilla root, are likewise 
incapable of yielding a good ink. The extracts of iron 
greening parts of plants do not yield pyro- gallic acid by 
dry distillation, unless they contain gallic acid ready 
formed " (Stenhause). This also shows the incorrectness of 



CHEMICAL THEORY OF THE TANNING PROCESS. 15 

the view advanced by Heniing, who regards the two 
groups as not essentially different from gallo-tannin, and 
as identical therewith, when pure. 

Dr. Lewis was the first to attempt a chemical analysis 
of nut-galls, about the middle of the last century, and he 
detected in them a substance "which coagulates with 
isinglass, and blackens the salts of iron." Seguin, how- 
ever, is believed to have been the first to accurately deter- 
mine the nature of this peculiar action upon gelatine, and 
also upon the skins of animals, and the term tannin was 
applied by him to this principle as existing in a variety 
of vegetable substances employed in the conversion of 
skins and hides into leather. Proust was the first who 
attempted to obtain tannin in a pure and separate state, 
and Sir H. Davy determined its relative quantity in a 
variety of tanning materials. It was not, however, until 
1834 that Pelouze discovered a method of separating 
tannic acid in a pure state (see p. 43). 

Although subsequent researches have to some extent 
disproved the theory which Seguin promulgated at a time 
when little was known of the principles of tanning, its 
reproduction here will not be out of place^.more espe- 
cially as it will enable us to give the views of other 
chemists of eminence concerning the weaker points of his 
theory. 

Seguin 's Theory of the Art of Tanning. — 1. The skin, 
stripped of its flesh, is a substance which can be easily 
converted by a convenient process into an animal jelly, 
which, concentrated and dried in the air, furnishes glue. 

2. A solution of this latter substance being mixed with 
an infusion of tan, an insoluble precipitate is formed, and 
this precipitate is not susceptible of putrefaction. 

3. The solution of tan is composed of two distinct sub- 
stances ; one precipitates the glue, and is the true tanning 
matter ; the other precipitates the protosulphate of iron, 
without precipitating the solution of glue, and produces 
only the disoxygenation of the skin, and of the substance 
which unites the hair to the skin. 

4. The operation of tanning is not a simple combination 



1 6 LEATHER MANUFACTURE. 

of the skin with, the principle which precipitates the glue, 
but a combination with the skin disoxygenised by the 
substance which in dissolution in the tan has the property 
of precipitating the sulphate of iron. Thus all substances 
to be used to tan ought to have the properties of precipi- 
tating glue and sulphate of iron. 

5. The operation of tanning consists, first, in the swell- 
ing of the skins by an acid principle ; second, a disoxyge- 
nation by gallic acid ; third, in disoxygenating the skin by 
the same principle ; and by this disoxygenation it is in a 
middle state between glue and skin ; fourth, in combining 
it by this disoxygenation. 

That Seguin was in error in supposing that gallic acid 
entered into the substance of the skin in any considerable 
proportion, if at all, there cannot be the least doubt. 
Indeed it has been abundantly proved that such is not the 
case, and the examination of the exhausted or spent tan 
liquors detects the presence of this acid in considerable 
proportion. Dr. Ure says, " In no case is there any reason 
to believe that the gallic acid of astringent vegetables is 
absorbed in the process of making leather ; hence Seguin' s 
theory of the agency of that substance in disoxygenating 
skin, falls to the ground." Dussauce* gives the following 
reasons for disagreeing with Seguin's theory : " Whatever 
are the merits of Segiiin, and the services he has rendered, 
we cannot but expose all the errors of the above theory. 
We persist in looking at the swelling of the skin as an 
effect less chemical than mechanical, which is principally 
due to the interposition of the water, or to the effect of the 
caloric produced by fermentation. Acids and alkalies act 
only as a means of preserving the skin from putrefaction ; 
afterwards they effect a chemical action. Thus the lime 
with which the interior of the skin is saturated, notwith- 
standing all the washings, forms with tannin a tannate of 
lime, which takes away the suppleness of the leather, and 
for this reason it is that the lime method is injurious. It 

* " Treatise on the Art of Tanning," &c. Edited from Notes and 
Documents of Sallerou, Grouvelle, Duval, Dessables, Labarraque, Payen, 
Rene, De Fontenelle, Malepyre, &c, &c. By Professor H. Dussauce. 



CHEMICAL THEORY OF THE TANNING PROCESS. 17 

is not the same with, acids. Besides preserving the skin 
from putrefaction, the acetic acid produced reacts on the 
fibrine, softens it, and transforms it partly into a trans- 
parent jelly, soluble in boiling water, and combining with 
the tannin. Besides this the acid, by which the skin is 
more or less saturated, precipitates the solution of tannin, 
and fixes a larger quantity in the leather. This softening 
renders the swelling very easy. However, it can be ope- 
rated without these means, which are in antagonism with 
Seguin's theory. 

' ' We do not agree with Seguin that gallic acid is the 
principal and indispensable agent in tanning. No experi- 
ment has demonstrated the durable disoxygenation which 
he asserts, and which is impossible, if we compare the 
respective constituents of gelatin and fibrin. Thus : — 

Fibrin contains 19-615 per cent, of oxygen. 
Gelatin ,, 72-207 „ „ 

" From this we see it is impossible that gallic acid dis- 
oxygenises the fibrine and transforms it into glue, whilst 
pure gelatin contains nearly one-half more of oxygen. If 
such were the case, gallic acid must oxidise instead of dis- 
oxygenising. We therefore see that this theory is inad- 
missible. Let us now record the experiment : — 

Catechu contains from 48 to 54 per cent, of tannin. 
Tea „ 34 to 40 „ „ 

Herb Bennet „ 42 „ „ 

Squill „ 24 „ „ 

" These substances, so rich in tannin, are applied with 
success in tanning ; while, however, they do not contain a 
particle of gallic acid. Seguin does not mention the ex- 
tractive ; however, this substance has some action in the 
tanning, and according to Sir H. Davy its presence is 
necessary to form a flexible leather, and in some way it 
may take the place of tannin. In England, where tanning 
material is very scarce, they have used the decoction of 
cicuta, and Schwerger has shown by analysis that 100 
parts of fresh leaves contain 2 '73 of extractive, without 

c 



1 8 LEATHER MANUFACTURE. 

tannin or gallic acid. To resume, we regard tanning as, 
a combination of five principles : fibrin, gelatin, tannin 
extractive, and acid. 

" 1. Gelatine and fibrin are transformed into a jelly by 
acetic acid, with tannin, extractive, and gallic acid. 

" 2. In tanning, the epidermis disappears, and no por- 
tions of the skin have been disoxygenated. 

" 3. The action of gallic acid is similar to that of acetic 
acid, and its presence is not necessary in the operation. 

"4. Extractive, like tannin, unites with the altered 
gelatin and fibrin, and renders leather flexible and firm. 
It is also their colouring principle ; thus leather tanned 
with gall is pale, that with oak bark brownish, with 
catechu reddish, &c. It is the extractive which gives the 
leather a brownish colour, without rendering it insoluble 
in boiling water. 

" 5. Lime forms with tannin a tannate of lime, which 
destroys the suppleness of the leather, and renders it dry 
and brittle. 

" 6. Dried skins, well tanned, increase in weight about 
33 per cent. This increase is due to the fixation of the 
tannin, extractive, gallic acid, (?) and a little water. 

"7. In saturated infusions there is less extractive than 
tannin,* which in weak solutions predominates. That is 
the reason why it is necessary to place the skins at first 
in very weak infusions, and lastly to saturate them little 
by little, with tannic acid and extractive, so as to have a 
complete tanning and more supple leather. 

" 8. By presenting to strong infusions, the leather con- 
tains but very little extractive, and is tanned only on two 
surfaces, the centre containing little, so that the leather 
obtained is hard and brittle. 

" 9. Lastly, gallic acid exercises so slight influence on 
tanning that Sir H. Davy thinks that it is doubtful if oak 
bark contains any." 

The above observations, taken collectively as the opinions 
of Dussauce, Malepyre, Pay en, Bene, Labarraque, de Fon- 
tenelle and others, and supporting as they do the views of 

* Davy. 



CHEMICAL THEORY OF THE TANNING PROCESS. 19 

that distinguished philosopher, Sir Humphry Davy, cannot 
fail to prove instructive to those who desire to pursue the 
art of tanning upon truly scientific principles. While 
disagreeing with Seguin's views as to the part which gallic 
acid plays in the process of tanning, we must not forget 
the great services he rendered to the followers of the tan- 
ning art by explaining the main principles upon which the 
art is based, and which, prior to his researches, were but 
little understood. 

As we have before shown, the process of tanning essen- 
tially consists in forming a chemical combination of the 
corium, or true skin of animals, with the vegetable astrin- 
gent principle tannin. If skins were merely dried — 
although they would possess a certain degree of hardness 
and durability while in that state, they would, when sub- 
jected to moisture, undergo putrefaction, and consequent 
speedy destruction. Again, untanned skins are pervious 
to water, and therefore cannot be used for the many pur- 
poses to which leather is so extensively applied. When 
skins are tanned, however, not only is their chemical con- 
stitution changed, but they are also rendered impermeable 
to water, besides being absolutely unputrefiable. More- 
over, during the combination of tannin with the skin 
it is believed that vegetable extractive matter from the 
bark, &c, also enters somewhat largely into the substance 
of the skin, to which, no doubt, some of the valuable pro- 
perties of leather are due. Sir H. Davy observes upon this 
subject: — 

" When skin is very slowly tanned in weak solutions of 
the barks, or of catechu, it combines with a considerable 
proportion of extractive matter ; and in these cases, though 
the increase of the weight of the skin is comparatively 
small, yet it is rendered perfectly insoluble in water, 
forming a soft, but at the same time a strong, leather. 
The saturated astringent infusions of barks contain much 
less extractive matter in proportion to their tannin than 
the weak infusions ; and when the skin is quickly tanned 
in them common experience shows that it produces leather 
less durable than the leather slowly formed. Besides, 



2 o LEATHER MANUFACTURE. 

in the case of quick tanning, by means of infusions of 
barks, a quantity of vegetable extractive matter is lost 
to the manufacturer which might have been made to 
enter into the composition of the leather." These observa- 
tions show that there is sufficient foundation for the opinion 
of the workmen concerning what is technically called the 
feeding of leather, in the slow method of tanning ; and 
though the processes of the art may in some cases be pro- 
tracted for an unnecessary length of time, yet in general 
they appear to have arrived, in consequence of repeated 
practical experiment, at a degree of perfection (in the 
quality of the leather) which cannot be very far exceeded 
by any elucidations of theory that have yet been made 
known. 

It must be confessed that the old tanners, although they 
may be said to have worked upon the rule-of-thumb prin- 
ciple, often had for their guidance those useful substitutes 
for scientific knowledge — good common sense and keen 
observation. Hence we find that they discovered, m prac- 
tice, that hides tanned slowly produced the best leather, 
in which view they were supported by Sir Humphry 
Davy, who found that saturated infusions of astringent 
barks contained much less extractive matter in propor- 
tion to their tannin than weak infusions. Davy further 
observes, " On the first view it appears singular that in 
those cases where extractive matter forms a certain portion 
of the leather, the increase of weight is less than when the 
skin is combined with pure tannin ; but the fact is easily 
accounted for when we consider that the attraction of skin 
for tannin must be probably weakened by its union with 
extractive matter ; and whether we suppose that the tannin 
and extractive matter enter together in combination with 
the matter of the skin, or unite with sejDarate portions of 
it, still, in either case, the primary attraction of tannin for 
the skin must be to a certain extent diminished." 

" In examining astringent vegetables," says Davy, 
" in relation to their powers of tanning skin, it is neces- 
sary to take into account not only the quantity they 
contain of the substance precipitable by gelatine, but like- 



CHEMICAL THEORY OF THE TANNING PROCESS. z\ 

wise the quantity and nature of the extractive matter; 
and in some cases of comparison it is essential to employ 
infusions of the same degree of concentration. It is evident 
that of all the astringent substances which have been as 
yet examined, catechu is that which contains the largest 
proportion of tannin ; and supposing, according to common 
estimation, that from 4 to 5 lbs. of common oak bark are 
required to produce 1 lb. of leather, it appears from the 
various synthetical experiments that about half a pound 
of catechu would answer the same purpose." 

Mr? Purkis found that 1 lb. of Bombay catechu was 
equivalent to 7 or 8 lbs. of oak bark ; and that, allowing 
for the difference in the composition of the different kinds 
of leather, 1 lb. of catechu, for the common uses of the 
tanner, would be nearly equal to 2^ lbs. of galls, to 7 lbs. of 
Leicester willow, to 11 lbs. of Spanish chestnut bark, to 
18 lbs. of elm bark, to 21 lbs. of common willow bark, and 
to 3 lbs. of sumac. 

Dr. Ure remarks,* "The older tanners, who prided 
themselves on producing a substantial article, were so 
much impressed with the advantages of slowly impreg- 
nating skin with astringent matter that they employed no 
concentrated infusion (ooze) in their pits, but stratified the 
skins with abundance of ground bark, and covered them 
with soft water, knowing that its active principles are very 
soluble, and that, by being gradually extracted, they would 
penetrate uniformly the whole of the animal fibres, instead 
of acting chiefly upon the surface and making brittle 
leather, as the strong infusions never fail to do. In fact, 
100 lbs. of skin, quickly tanned in a strong infusion of 
bark, produce 137 lbs. of leather; while 100 lbs., slowly 
tanned in a weak infusion, produce only 117^ lbs. The 
additional 19 \ lbs. weight in the former case serve merely 
to swell the tanner's bill, while they deteriorate the leather 
and cause it to contain much less of the textile animal 
solid. Leather thus highly charged with tannin is, more- 
over, so spongy as to allow moisture to pass through its 
pores, to the great discomfort and danger of persons who 

* "Dictionary of Arts, Manufactures," &c. By Andrew "Ore, M.D. 



23 LEATHER MANUFACTURE. 

wear shoes made of it. That the saving of time and the 
increase of product are temptations strong enough to 
indtice many modern tanners to steep their skins in a 
succession of strong infusions of bark is sufficiently intel- 
ligible, but that any shoemaker should be so ignorant or 
so foolish as to proclaim that his leather is made by a 
process so injurious to its quality is unaccountably stupid." 
During the process of tanning, more especially by the 
modern system, in which infusions of bark and other 
tanning materials are used, chemical decomposition of a 
portion of the tannin takes place by a process of fermenta- 
tion, by which gallic acid — a useless product to the tanner 
— is formed. This will be considered in the chapter on 
Gallic. Fermentation, and the various remedies for its pre- 
vention duly given. 



CHAPTER II. 

THE SKIY. 

The Skin. — Structure of the Skin. — Mr. Ashe's Description of the Skin. — 
Composition of the Skin. 

The Skin. — It is of the first importance to the tanner 
that he should be acquainted with the anatomical structure 
of that part of the animal — the skin — the treatment of 
which constitutes his art. This knowledge is more espe- 
cially necessary, since not only does the cuticle, or outer 
surface of the skin, resist the action of the tanning prin- 
ciple, hut the underlying substance, the true shin, when 
brought in contact with tan, or tannin, undergoes a defi- 
nite chemical change, by which its whole character and 
properties are completely altered. 

Structure of the Skin. — The skin of animals consists of 
two distinct layers, which are thus classified : 1. The 
Cuticle, epidermis, or scarf skin; and 2. The Cutis, corium, 
or true skin {cutis vera) . The cuticle varies in thickness in 
different animals, and in different parts of the body ; it is 
insoluble in water, alcohol, and dilute acids ; strong acids 
soften it, and ultimately dissolve it, while solutions of 
caustic alkalies, as soda and potassa, freely dissolve it, 
even when very dilute. The cuticle readily absorbs cer- 
tain colouring matters, which impart to it a permanent 
dye. Between the cuticle and the corium is the areolar 
tissue, formerly termed the rete mucosum, in which the 
roots of the hair are embedded. This tissue contains the 
colouring matter which gives to the skin its characteristic 
tint, and which is much influenced by the action of light. 
" The black skin of the African," says Brande, " the 
brown of the Asiatic and American, and the pinkish -white 



24 LEATHER MANUFACTURE. 

of the European, derive their colour from this peculiar 
secretion deposited between the cutis and cuticle; the 
nature of this substance has not been chemically investi- 
gated, but it has been ascertained, in regard to the black of 
the negro, that it admits of being bleached by chlorine." 

The cutis, or true skin, is of a fibrous texture, almost 
wholly soluble when boiled in water, and the solution, 
when cold, forms a tremulous jelly, which is gelatine — the 
chief constituent of the cutis, or that part of the skin 
which, when submitted to the action of tannic acid, consti- 
tutes tanned leather, or more properly, tanned skin. 

The structure and functions of the human skin are 
admirably described by Mr. Ashe in a valuable paper upon 
this subject ; although objection may be taken to our 
having chosen this author's description of the human skin 
instead of giving that of the ox or other inferior animal, 
we venture to suggest that for the purposes of the tanner, 
who practically requires merely to know the structure of 
the skin and its functions generally, without troubling him- 
self about the comparative anatomy of the subject — the 
full and minute description given by Mr. Ashe will enable 
him to comprehend the true character of the delicate 
fibrous structure of the cutis, which, when separated from 
its cuticle, hair, and fleshy matters, constitutes the pelt or 
part of the hide to be tanned. Moreover, when the fibrous 
texture of the unhaired skin is thoroughly understood, the 
tanner is better able to regulate and control its proper 
treatment in the various stages of the several processes 
which constitute the art of tanning. 

Mr. Ashe's Description of the Skin. — " The cutis, or 
true skin, rests upon a very fine interlaced or netted struc- 
ture, called the areolar tissue, out of which, if we may so 
express it, the granules and fibres of the skin are formed. 
The cuticle, or scarf skin, is never of any great thickness 
in any animal, but the true skin is of very variable thick- 
ness. In the whale the cutis attains the thickness of about 
an inch, which is the greatest known in any animal. The 
cuticle consists of several layers of laminated scales, the 
laminated form being best marked at the very surface, 



THE SKIN. *5 

where the scales are constantly falling off, as a kind of 
scarf, and are as constantly being renewed from below. 
These scales are formed by the flattening out of granules, 
more or less rounded, which is the form assumed by the 
particles of the cuticle in its deeper layers. These granules 
are at first nucleated* cells, and the colouring matter of 
the skin resides in the nuclei ; and it was these granules 
that were formerly described as a separate layer, under the 
name of rete mucosum. They are very minute, being 
about -g- o'oo" P ar ^ °^ an ind 1 i n diameter at first. Being 
removed from below, as the flattened scales are removed 
from above, they gradually approach the surface, and as 
they do so they more and more lose the granular form, and 
assume the scaly character, their diameter increasing 
accordingly to about -q^ of an inch. Into the epidermis, 
or cuticle, no nerves or blood vessels penetrate, and it is 
nourished merely by the transudation f of the serum of the 
blood through the walls of the vessels of the true skin and 
subcutaneous areolar tissue. It is not itself sensitive, but 
on the contrary, serves to blunt the too exquisite sensation 
of the true skin, which is much more highly organised, 
and consists of two kinds of tissue, namely, white and 
yellow fibres, the former being denser and more resisting, 
and being therefore present in greater quantity wherever 
resistance is most needed, as in the palm of the hand and 
sole of the foot ; while the yellow fibres are a highly elastic 
tissue, owing to their minute fibrillse being arranged in 
interlacing curves ; and the fibres cross each other repeat- 
edly, and branch, so as to form lozenge-shaped interstices, 
which are filled up principally by the white fibres. The 
yellow fibres accordingly, as might have been anticipated, 
exist in greater abundance where elasticity is a special 
requirement, as at the flexures of the joints, the lips, &c. 
The uppermost surface of the cutis, or true skin, is strangely 
uneven and irregular, being elevated into a vast number of 
minute papillae, which are about -y^- of an inch in height 
and -jyo" °f an ^ ncn i n diameter. Minute as these little 

* From nucleus, a body round which, anything is collected or deposited. 
1 Passing through as vapour. 



26 



LEATHER MANUFACTURE. 



papillae are, each possesses a ramification of vascular capil- 
laries, and of nerve fibres, being, in fact, the essential 
agents in the sense of touch, for that is the function of 
these papillae. The skin of the tongue in men and animals 
shows the papillae larger than in any other part of the 
body." The accompanying illustration (Fig. 1) represents 

a highly magnified view of 
the skin, with its secreting 
glands and perspiratory 
ducts, a is the cuticle, or 
scarf skin ; b the areolar 
tissue, and c the cutis, or 
true skin. 

" The true skin is perfo- 
rated by perspiratory ducts 
(/), and when the hand is 
warm the perspiration may 
be observed, even with the 
naked eye, to issue from 
them, forming minute shin- 
ing dots. The glands (e) by 
which the perspiration is 
secreted, are seated at the under surface of the true skin, 
each embedded in a cavity of it. These glands are con- 
sequently to be regarded as true excretory organs, re- 
moving from the blood materials that are no longer 
wanted, and which, if retained, would be injurious. About 
2,500 of these ducts are found in the square inch of 
the skin. 

"Another kind of gland is also formed in the skin, in 
connection with the hairs, and engaged in their nutrition ; 
these glands are called sebaceous glands (d) ; the ducts of 
these glands are not spiral, and they open generally into the 
hair follicles or pits which the hair grows out of, situated 
in the subcutaneous areolar tissue ; these glands lubricate 
the skin, and so maintain its elasticity : and they also 
eliminate hydrocarbons from the skin." 

It will be seen from the above observations that the 
direction of the secreted fluids of the true skin is outward, 




Fie. 1, 



THE SKIN. 27 

or in the direction of the cuticle, consequently the absorp- 
tion of tanning material would be more powerful at the 
flesh side than at the grain side of the skin. 

Composition of the Skin. — A piece of fresh skin, freed 
on its internal side from fat and cellular tissue, and on its 
external side from the epidermis (cuticle) and the mucous 
membrane (areolar tissue), which lies between the epider- 
mis and the true skin, contains about 43 per cent, of solid 
matter, the remainder being water. Of the solid matter 
about 32 per cent, of the weight of the humid skin is the 
fibrous and cellular tissue, and a little fatty matter, each 
of which is insoluble in cold water ; 1*5 per cent, is unco- 
agulated albumen. About 1 per cent, is a variety of 
extractive matter, soluble in water and alcohol, and 7 "5 per 
cent, is another kind of extractive matter, soluble in water, 
but insoluble in alcohol. — Wcinholt. 

Nearly the whole of the albumen and other matters 
capable of being dissolved by cold water may be separated 
by digesting the skin in that liquid. When the washed 
skin is dried and digested in ether, a small quantity of 
fatty matter is dissolved out. By digestion in boiling 
water the greater part of the true skin becomes altered in 
properties and dissolved ; only some vascular and nervous 
filaments, with a little fat, remaining undissolved, and the 
solution, when slowly evaporated, leaves a residue of gela- 
tine, or glue. — Parnell. According to Berzelius, gelatine 
does not exist, as such, in the living body, but several animal 
tissues, such as skin, cartilages, tendons, the serous mem- 
branes and bones, are susceptible of being converted into it 
by the action of boiling water. The term gelatinous tissue 
is commonly used to designate all animal tissues which are 
convertible into gelatine by such a process. Dilute acids 
and alkalies possess the property of converting gelatinous 
tissues into gelatine even at the ordinary temperature. 



CHAPTER III. 

HIDES AND SKINS. 

Classification of the Skins of Animals. — Condition of Hides and Skins. — 
Hides. — Native Hides. — Dried Hides. — Salted Hides. — Dried Salted 
Hides. — Selection of Hides. — Warbles. — Abusive Treatment of Raw- 
Hides. — Kips. — Buffalo Hides. — Horse Hides.- — Ass and Mule Hides. 
— Hippopotamus Hides. — Calves' Skins. — Sheep Skins. — Lamb Skins. 
— Goat Skins. — Kid Skins. — Hog and Pig Skins. — Seal Skins. — Deer 
Skins. — Porpoise Skins. — Serpent and Crocodile Skins. 

Classification of the Skins of Animals. — These are 
known, commercially, under three different heads, namely 
— 1. Hides, or the skins of the larger and full-grown 
animals, as the ox, cow, bull, buffalo, horse, and hijDpopo- 
tamus ; 2. Kips, or the skins of the smaller Indian 
animals of the bovine class ; and 3. Shins, as those of the 
smaller animals, such as the calf, sheep, goat, deer, &c. 
The skins which are most extensively used in the manu- 
facture of the various kinds of leather are those of the 
ox, cow, bull, horse, calf, sheep, goat, kid, pig, deer, seal, 
and kips; but the skins of crocodiles, alligators, and 
even serpents are also employed for making certain kinds 
of fancy leathers. 

Condition of Hides and Skins. — The quality of hides 
and skins is greatly influenced by the conditions under 
which the animal has grown, the nature of its food, the 
variety of breed, climate, the state of its constitution, its 
age, and the time of year at which it has been slaughtered. 
The hides of the larger oxen form, when tanned, a stouter 
and heavier leather than those of cows, especially if the 
latter are from old animals or from those which have 
calved several times. The hides of bulls are of coarser 
grain and thinner in the back, or butt, than those of oxen 
and heifers, or young cows, although they are stouter in 



HIDES AND SKINS. 29 

the neck and certain parts of the belly. Muspratt says, 
" Hides of animals dying in a state of disease are found to 
be much inferior to those of healthy ones of the same 
class, although the apparent difference is not very marked 
before tanning. No very definite criteria are known to 
guide the purchaser in distinguishing the quality of hides 
and skins. If the hide be thin, flabby, soft, and will not 
bear handling, then such a one will not make good leather ; 
but should it present the opposite qualities, it may be con- 
fidently expected to be a good article. It has been remarked 
of sheep that the skin gains in thickness and quality con- 
siderably in the course of a few days after shearing. 5 ' 

Hides. — Under this heading are included the skins of 
oxen, cows, horses, and buffaloes. The hides are distin- 
guished as — 1. Fresh, or green hides, or those which come 
from the slaughter-houses of Great Britain ; 2. Dried hides, 
as imported from Buenos Ayres, the Cape of Good Hope, 
&c. ; 3. Salted hides, those which come from Bio Grande, 
Biver Blate, Australia, &c. ; and 4. Dried and salted hides, 
as imported from Brazil, Mauritius, West Indies, and other 
countries. Although the hides of home production are held 
in the highest estimation, the imported dried and salted 
hides, when subjected to certain preparatory processes to 
bring them into the condition of green hides, form, when 
tanned, most excellent leather. The trouble, and labour 
involved in softening the dried skins naturally favours a 
more ready market for those of home production ; neverthe- 
less we import enormous quantities of hides and skins from all 
parts of the world, but more especially from South America. 
The vast pampas through which the Biver Blate (or Silver 
Biver) and its tributaries flow, yield boundless pastures ■ 
for wild or partially wild oxen and horses, which have 
been estimated to number nearly 25,000,000. Indeed, the 
climate of this district seems specially suited to the rearing 
of cattle, which are descended from the tame animals first 
introduced by the Spaniards after Columbus' discovery. 
The Buenos Ayres hides obtained from the most southern 
states are considered stouter and of finer texture than those 
of Uruguay or Bio Grande. The hides from the more tern- 



30 LEATHER MANUFACTURE. 

perate regions are salted, and exported as wet salted, while 
those from the tropics are generally dried in the sun, or 
salted and dried. Dry salted hides are largely exported 
from Brazil, Mauritius, Madagascar, &c. 

Native Hides, or those of home slaughter, differ greatly 
in substance, size, and texture ; while those from the south 
of England yield large and heavy hides of fine texture and 
grain, they are much thinner than the smaller hides of the 
north of Scotland. The fattening of cattle for the produc- 
tion of good beef, to suit the English market, renders the 
hides, although of great size and weight, considerably 
thinner than those from cattle subjected to less culture. 
The hides of heifers are preferred to those of cows which 
have calved several times, owing to the latter being thinner 
and of poorer substance. Bull hides are not liked by 
the tanner, owing to their Want of uniformity in sub- 
stance, being thin in the back and thick at the shoulders 
and the surrounding parts called offal. Ox hides generally 
weigh from 60 lbs.* to 120 lbs., cow hides from 40 lbs. to 
80 lbs., and kips from 20 lbs. to 22 lbs. 

Dried Hides — These are sometimes called "flint" 
hides, from their excessive hardness. It is well known 
that when skins are dried in the sun they become nearly 
as hard as horn, and when in this condition, they require 
much soaking, rubbing, and beating to bring them to the 
proper state for treatment in the lime pits. The imported 
dried hides of Buenos Ayres, Monte Yideo, and other 
countries are, however, extensively used by the tanner, 
and from them leather of very good quality is produced. 

Salted Hides. — The salted hides from South America 
come into this country in a moist condition, a large quan- 
tity of salt being stratified between each hide. Since the 
salt, however, adds considerably to the weight of the hides, 
it is usual for the intending purchaser, when inspecting 
them at the docks while the vessel is unloading, to turn 
them over before having them weighed, to free them 
as far as possible from the loose salt ; while doing so he 

* Hides are reckoned small, and of less value in proportion, when they 
weigh 60 lbs. and under. Over this weight they rank as large hides. 



HIDES AND SKINS. 31 

is able at the same time to form a fail judgment as to 
their condition. These hides are frequently impaired by 
the barbarous system of branding adopted by the South 
American cattle owners, sometimes as many as half-a- 
dozen brands being visible on a single hide. These im- 
pressions of the branding-iron render such parts of the 
hide useless when tanned, whereby the manufacturer neces- 
sarily suffers loss. Unsuccessful attempts have been made 
from time to time to induce cattle owners to adopt some 
less brutal and injurious system of marking their cattle. 
Probat)ly the most effectual remedy for the evil would be 
to reject all such heavily branded hides. 

Dried Salted Hides. — The hides from Brazil, Mauritius, 
West Indies, and the Cape sometimes come into the market 
both dried and salted, in which condition they are more 
readily brought to a pliant state than the so-called " flint," 
or dry hides. 

Selection of Hides. — Although judgment based upon 
practical experience is the only reliable guide in the selec- 
tion of hides and skins, there are several points to which 
special attention may be directed. 1. The hide should pre- 
sent the appearance of having been well flayed, free from 
cuts or gashes produced by the slaughterer's knife, and pre- 
sent little or no sign of decomposition. 2. The hide should 
not be loose and flabby, but generally firm in substance. 
3. Besides being stout in the back, or butt, it should ex- 
hibit this quality, though in a gradually diminishing 
degree, right up to the shoulder. 4. The hide should be 
free, or as free as possible, from icarbles or warble marks, 
more especially if to be used in the preparation of harness, 
bucket, or hose leather. These defects, which are pro- 
duced by the larva, or grub, of the bot, or gadfly (oestrus 
bovis), sometimes cause serious injury to the most important 
portion of the hide — the back ; and although warbles are 
of less consequence in the production of sole leather, they 
would be fatal to leather which is required to be wind or 
water tight. Since the subject of warbles is a very im- 
portant one, and has received much attention from ento- 
mologists and others, it may be well to consider the origin 



32 LEATHER MANUFACTURE. 

and nature of the destructive parasites which produce the 
holes, or warbles, in the hides of cattle. 

Warbles. — Some persons seem to have entertained the 
idea that the grub which perforates the skin of oxen is de- 
veloped much in the same way as the trichince, from which 
the devourers of uncooked ham and bacon, and German 
sausage, suffer — chiefly in Germany — in the form of disease 
known as trichinosis. We think, however, that the most 
reliable evidence is in favour of the entomologists, who have 
universally attributed the pest to the gadfly, an insect 
which is well known to haunt the meadows in which cattle 
feed, and to cause the animals much pain and suffering. 
It appears to be conclusive that the gadfly first pierces the 
skin with an organ termed an ovipositor — much in the same 
way that a wasp's sting is introduced — and that in the 
hole thus formed an egg is deposited, which after a time 
becomes hatched. The existence of the liberated grub 
beneath the skin causes great irritation, and an open sore 
is established, which extends as the larva increases in size. 
When it has become fully matured, it escapes from the 
hole, and falls to the ground, where it in time changes to 
the pupa, or chrysalis state, from which, in the following 
season, the pretty but dreaded new-born fly emerges to 
carry on the war with the bovine race. The distinguished 
naturalist, Sir John Lubbock, says, " The gadfly deposits 
its eggs upon the bodies of animals, and the grub feeds 
inward when hatched." Another writer in The World 
of Insects says : " The gadfly at certain seasons attacks 
oxen, not to bite and suck their blood, but to deposit its 
eggs in the hides of the cattle — an operation which is not 
put into execution without occasioning considerable pain. 
The circular hole thus made always continues open, and 
increases in diameter as the larva increases in size, which 
thus enables a continual supply of fresh air * to reach the 

* It may be doubtful whether air is really necessary to the existence 
of these maggots, since the trichince, tape worms, ascarides, and other 
well-known parasites seem to get on very well in the animal system 
without troubling themselves about a "breath of fresh air." An animal 
that thrives upon purulent and decomposing matter may be said to be not 
very particular as to " fresh air." 



HIDES AND SKINS. 



33 



insect. But although they torment and terrify the cattle 
during the time of ovipositing, they do them in reality no 
material harm; indeed tanners prefer hides that have 
the greatest number of bot holes, considering them the 
strongest and best, which indeed they are, as the gadfly 
never attacks any but young and healthy subjects." This 
seems an extraordinary statement, and one which the 
mind cannot readily accept as based upon reasonable 
ground. That young and healthy animals should be pre- 
ferred by the anxious parent for the boarding and lodging 
of her progeny is quite natural and to be applauded ; but 
that it should be stated that tanners prefer perforated to 
sound hides seems inexplicable, more especially as it is 
so very well known that how to get rid of warbles has 
been one of the most anxious subjects of inquiry connected 
with the trade for many years. 

Referring to the ox-bot or ox-gadfly, another writer ob- 
serves — " It is a beautiful insect, not quite half-an-inch 
long, and thicker in proportion than the horse-bot. It 
has brown, unspotted wings, the face whitish, the crown 
of the head brown, the thorax black, the abdomen whitish, 
with a broad black band round the middle, and yellow 
hairs at the extremity, where also the female has an ovi- 
positor — a remarkable organ, formed of a horny substance, 
consisting of four tubes, retractile within one another, like 
the pieces of a telescope, and the last of them terminating 
in five points, three of which are longer than the others, 
and hooked. By means of this organ, a small round hole 
is pierced in the hide of an ox's back, in which an egg is 
deposited. The fly is very quick in depositing her egg — 
not remaining on the back of the animal more than a few 
seconds. Cattle exhibit great alarm and excitement at 
the presence of the gadfly, and rush wildly about with 
head stretched forward, and tail stuck out, to escape from 
their tormentor. The further injury done by this insect 
is not, however, usually great, the larva — a little pearl- 
white maggot feeding upon the juices of the skin — caus- 
ing a swelling, called a icarble, forming a sort of sac, 
within which it lives and grows amidst a kind of purulent 

D 



34 LEATHER MANUFACTURE. 

matter suited to its appetite, and from which it usually 
emerges, leaving a small sore ; and, like the horse-bot, 
undergoes its further transformation in the ground." 
Again, Miss Eleanor A. Ormerod, who had worked assidu- 
ously with the farmers in their efforts to diminish the 
injuries caused by insects to their crops, writes : " The 
oestrus bovis is a largish two-winged fly, and the female 
lays her eggs on the backs of horned cattle. The maggots 
from these, by feeding on the flesh, cause tumours, with 
an opening at which orifice the tail end of the maggot is 
usually exposed. When full fed, the larva, or maggot, 
drags itself out of the tumour and falls to the ground, 
where it changes to the pupa or chrysalis state, from which 
in due time the rather handsome fly emerges." 

The above observations clearly prove the origin of 
warbles, and when it is borne in mind that, besides the 
positive injury done to the hide, the animal must suffer 
great and continual torture, it would be well if our agri- 
cultural chemists and scientific farmers were to devote 
special attention to the subject, with a view to discover 
some means of rendering the skin of young cattle less 
attractive to the gadfly. This might be accomplished, 
possibly, by brushing over that part of the skin (the back) 
which is generally selected as the depository of the gad- 
fly's eggs, some oil, or solution of such substances as 
are known to be objectionable to insects, but harmless to 
the animals themselves. It is well known, for example, 
that the smell of the oil of birch is much disliked by most 
insects, as also is creosote, or water impregnated with it. 
Again, powerful bitters, as wormwood, quassia, and aloes, 
are repugnant to some species of insects. If, therefore, 
during that period of the year when the gadfly makes its 
appearance, the backs of cattle were brushed over with one 
or other of these agents, is it not probable that the fly, 
recognising a foreign flavour or odour upon the skin of the 
animal, would abandon it and fly from beast to beast in 
search of one more suited to its purpose ? Doubtless the 
gadflies emerge from the shell of the chrysalis with toler- 
able regularity as to time, in which case the appearance of 



HIDES AND SKINS. 35 

the first insect of the season would be a signal for the 
application of any agent which it was desired to try with a 
view to determine whether a remedy for warbles could be 
found in the direction we have indicated. 

Abusive Treatment of Raw Hides. — Ordinary care- 
lessness and even rough usage, of a raw material so difficult 
to handle as the hide of such a large animal as the ox, can 
neither be wondered at nor prevented, but apart from this, 
hides are too often abused, in various ways, to such a degree 
as greatly to reduce their value to the tanner. Some years 
ago M? H. Lange, a Cordovan leather tanner, at a meeting 
of the trade at Oschatz, exposed the abuses to which hides 
were subject before they fell into the hands of the tanner ; 
and since his observations are applicable to all times and 
places, their reproduction here will doubtless be acceptable 
to our readers. 

" M. Lange expressed his regret that in the prepara- 
tion of the hide for trade purposes, raw hides and skins 
laboured under great disadvantages, owing to the farmers' 
and butchers' handling, inasmuch as this was not carefully 
done with a view to the future operations to be undergone 
by the raw material. The bark and white tanners present 
at the meeting, also gave expression to the united wish 
that through making known the manipulations which 
experience has proved to be the most simple and at the 
same time the most efficacious, hides or skins may be 
delivered in a condition perfectly suitable to the process of 
manufacture, and the evils specified may hereafter be done 
away with as far as possible. It too often happens that 
hides and skins of slaughtered animals, as of those that 
have died from natural causes, are not at once taken off, 
but left for days on the carcase. This is in the highest 
degree detrimental to the hides, as they acquire thin and 
defective spots through decomposition going on in the 
carcase, or the worms which are forming in the interior of 
the animal [query] work destructively upon the hides. 

" Great damage is also caused, although not of so serious 
a nature, if, in flaying, the work is not done with all due 
care. The bits of flesh and fat, which are too often allowed 



36 LEATHER MANUFACTURE. 

to remain adhering to the hides and skins, become at once 
decayed and communicate decay to the skin, which is 
injured or eaten away in spots, becoming consequently, 
and subsequently, very thin, or even worn into holes. Such 
damage is noticeable more especially after manufacture, 
when the leather is found bad in appearance or pitted 
with dark spots, as in the case of coloured leather. Leaving 
these defects out of the question, the suppleness and dura- 
bility of the leather itself will be injuriously affected if the 
skins are not suitably and carefully treated in drying and 
hanging up, by the premature shrinking and imperfect 
drying of the material. As evidence that the evils just 
mentioned, arising from improper treatment, are of more 
importance than is generally thought, M. Lange states 
that the sheepskins received in the summer season often 
yield barely one-third of the material perfectly adapted to 
the manufacture of imitation Morocco leather. 

" In view of these evils, and in order to promote the 
interests of the leather trade, the following points are to 
be urgently recommended to the slaughterers in flaying 
hides and skins : — 

" 1. Immediately after the death of the animal the hide 
or skin should be carefully taken off. 

" 2. The fleshy or fatty portions still adhering to the 
skin should be detached, down to the smallest pieces. 

" 3. The hide should, without the least delay, be hung 
up in a very airy place, and one not exposed to damp, with 
the hair side inward, so that the draught of air may play 
upon the entire length of the flesh side of the hide. 

" 4. In order to prevent the hide from shrinking, the head 
and tail ends should be stretched out and nailed to the pole. 

" 5. The hoofs and legs should be spread with skewers 
on both sides. 

" 6. The flaying of the hide should not be entrusted to 
inexperienced persons; for unless a certain dexterity is 
brought into operation, the value of the skin will be con- 
siderably lessened. Only by observing these directions, 
can 'the skins and hides be properly dried and delivered 
free from defects, suitable for valuable use. The benefits 



HIDES AND SKINS. 37 

that will accrue to the whole leather trade by following 
such a course canuot be rated too highly, for not only will it 
secure a serviceable material to manufacturers, but also a 
large quantity of hides and skins will be saved from 
destruction, and the market will be better and more fully 
supplied. A further consequence will also be that a better 
manufactured article will be produced and lower prices 
established." — Dussauce's Treatise. 

A few years ago Mr. George Middleton, manager of 
the Midland Counties' Butchers' Hide, Skin, &c, Com- 
pany (Limited), suggested the plan of issuing cheques to 
slaughtermen, entitling them to a reward of sixpence for 
each hide taken by the company flayed to its satisfaction. 
In addition to this, the master butchers agreed to give an 
extra sixpence per hide, as a reward for careful flaying, 
thus giving the slaughtermen one shilling per hide for 
performing their work with extra, that is proper, care. 

Kips, or skins of the younger and smaller animals, are 
largely imported from the East Indies, the Cape, Australia, 
North and South America, and elsewhere. From the East 
Indies they arrive either dry, dry salted, or brined — that 
is, simply salted. The E. I. kips are the skins of a small 
breed of oxen, and being derived from full-grown animals 
they are in reality hides. Besides being imported in either 
of the above conditions, a large quantity reach our market 
in the tanned state. The importation of E. I. kips amounts 
to millions of skins annually. Kips are also imported 
from the countries surrounding the Baltic, but these 
are generally obtained from animals slaughtered when 
young, and therefore are more of the character of skins 
than hides. The smaller and inferior varieties of kips 
and calfskins are tanned for the purposes of the book- 
binder and glover, and also in the preparation of 
leather for uppers of the lighter kinds of boots and 
shoes. 

Buffalo Hides. — These are imported from various parts 
of the East Indies — as Bombay, Calcutta, Batavia, Kur- 
rachee, &c. These hides make an inferior kind of sole 
leather, and are tanned in the same way as ox hides. Eor 



38 LEATHER MANUFACTURE. 

certain purposes, however, they are tanned in a peculiar 
manner, and then form what is known as buff, or belt 
leather, which possesses superior strength to the same article 
prepared from cow hides. The annual importations have 
sometimes amounted to upwards of 300,000 hides. 

Horse Hides. — The best horse hides are those which 
are imported from the River Plate, Rio Grande, and other 
parts of South America. The wild horses of the pampas, 
which are captured and slaughtered chiefly for the hides 
and fat, furnish a vast supply of hides, which are greatly 
superior to those of our own market, which are generally 
from old and worn-out animals. The skin of the horse is 
nrach inferior to that of the ox, or even cow, as to strength, 
texture, and thickness, and is therefore not suitable for 
making sole leather ; a small portion of the back, or butt, 
nearest the animal's rump, however, is generally cut away, 
and when tanned is employed for upper leather (" crap "). 
The better qualities of horse hides are tanned for uppers 
of boots and shoes, but the chief purpose to which they 
are applied is in making Cordovan, or enamelled leather. 
For this purpose the pelts are split by machinery, which 
reduces them to any required thinness. These hides are 
also tawed, or alumed, and converted into white leather 
for workmen's aprons, for the thongs of common whips, 
and other useful purposes. 

Ass and Mule Hides. — When tanned, these hides form 
what is known as Shagreen, or Shagrin. 

Hippopotamus Hides. — Only a limited number of these 
skins come into the market, being imported from the south 
of Africa. They are of remarkable thickness, and when 
tanned are exceedingly hard. The principal purposes to 
which the tanned hides are applied is for implements used 
in washing and bleaching cotton and linen goods, and for 
making circular "buffs" for polishing brass and other 
metals. Walrus hides are also used, when tanned, for 
similar purposes. 

Calves' Skins, of home produce, are of very superior 
quality, and, when tanned with oak bark, produce a 
leather which is very extensively used for the uppers of 



HIDES AND SKINS. 39 

shoes and for boot fronts. In France, which is famous for 
the excellence of its calf-skin leather, the calves are 
slaughtered when about five or six months old. 

Sheep Skins. — The supply of sheep skins in the home 
market is very extensive, and besides this source of supply 
an immense number are imported from South America, the 
Cape, Australia, and many other countries : a very con- 
siderable proportion come to us in the tanned state. 
Although sheep skins produce but a very weak, spongy 
leather, they are applied to a great variety of purposes. 
When tanned with bark, they constitute bazils, and are 
used for making slippers, and also as bellows-leather ; 
when tawed, or prepared with alum and salt, they form 
what is termed white leather, which is much used by drug- 
gists, and also for workmen s aprons. Sheep skins are very 
often subjected to the operation called splitting, when the 
grain side is tanned with sumac, and dyed, and is after- 
wards worked up as imitation morocco, roan, or shiver, into 
covers for pocket-books, for hat linings, &c. The flesh side 
is converted into white leather for druggists' use, or into 
chamois, or shammy leather ; for the former, however, lamb 
skins are most generally employed. Sheep skins are some- 
times tanned with the wool attached, and converted into 
mats ; or tawed, and made into housings. For these pur- 
poses the best skins are selected, and those with the longest 
and most beautiful fleece are chosen by preference. 

Lambs' Skins are very extensively used in the prepara- 
tion of leather by the process of taioing, for glove-making, as 
a substitute for kid leather, and for various other purposes. 
Besides the very large number produced in this country, 
great quantities of lambs' skins are annually imported. 
There is a great difference in the quality of these 
skins ; those from the animals slaughtered shortly after 
birth possess an exceedingly fine grain and are sus- 
ceptible of a very uniform dye — an important feature in 
skins used for ladies' gloves. This extreme delicacy of 
texture is retained by the skin of lambs until after they 
are a month old, from which period they gradually lose it. 
In the south of France and in Italy considerable numbers 



46 LEATHER MANUFACTURE. 

of lambs are killed averaging four weeks old ; leather pre- 
pared from these skins is largely used for " kid " gloves. 

Goat Skins. — A very extensive trade is carried on in 
Great Britain and Ireland in these skins, and also in the 
tanned and tawed leather produced from them. In 
Ireland a large number of skins of native produce are 
used, but Great Britain is supplied chiefly by imports 
from Switzerland, and the Yalley of the Bhine, and also 
from India and the Cape of Good Hope, from which 
latter places they are imported in the dry state. Millions 
of these skins, however, come into the British market 
already tanned and tawed from these countries. The Swiss 
goat skins are most highly esteemed, owing to the very 
fine, close and uniform texture of the grain, which enables 
the dyer to impart a brilliant and permanent colour ; the 
leather prepared from Swiss skins is said to be stronger 
and more durable than any other manufactured from goat 
skins. A very considerable number of these skins are 
annually converted into morocco leather for various uses 
in the different branches of the trade. The goat skin 
tanned and dyed on the grain side constitutes true morocco 
leather. Mogadore skins are made into a kind of black 
morocco, called Cordovan, in consequence of the first sup- 
plies of the article being obtained from Spain and Cordova, 
where the Moors originally brought the manufacture to 
great perfection. The sound skins which arrive from the 
Cape of Good Hope, are much larger and superior in 
strength and thickness to any other variety. East India 
skins are small and light, and are generally converted into 
chrome leather chiefly used for ladies' shoes. Those 
from Mexico, known in the American market as Tampico 
skins, bear a very high character. Compared with sheep 
skins, those of goats are much superior in texture, 
strength, and durability. Goat skins are occasionally 
prepared so as to imitate chamois leather, and applied to 
most purposes to which the latter is adapted ; and like- 
wise with the hair on, and used for matting. — Muspratt. 

Kid Skins, converted into leather by the process of 
tawing, are very extensively used in the manufacture of 



HIDES AND SKINS. 41 

gloves, and also for slippers, or light shoes ; by druggists 
for covering the corks of bottles, and for other useful 
purposes. The kid skins of France — from which the 
famous " French kid " gloves are made — have always 
been held in high estimation, as also are those of Ireland. 
After the animal begins to feed upon herbage, the 
skin loses in delicacy of texture, and therefore becomes 
unsuited for the finest gloves. There can be no doubt 
whatever that from the time the young animal ceases to 
derive its sustenance from the mother, and feeds upon 
vegetable substances, a greater degree of solidity and 
firmness of texture is acquired by the skin, as also by all 
other parts of the body, and as a consequence the elasticity 
and extreme fineness and delicacy in texture of the skin 
gradually become deteriorated. 

Hog and Pig Skins. — The practice of skinning swine 
is carried on in Scotland, and also on the Continent, and 
the skins, when tanned, form a very light and porous, but 
still very tough and durable leather, which is extensively 
used by harness makers, and also for the seats of saddles. 
On the Continent the hide is dressed with the hair on, and 
is employed for covering portmanteaus, knapsacks, &c. 
Pig skin is also used for leather breeches, but not to such 
an extent as formerly. 

Seal Skins. — These valuable skins are imported into 
this country in very considerable quantities, from British 
North America, Newfoundland, the United States, the 
Whale Fisheries, Norway, the Cape of Grood Hope, and 
other localities. The skin of the seal is light, and of very 
close texture, and when properly tanned is considered to 
produce a leather of greater strength in proportion to its 
weight than any other kind of leather. Seal skins are 
commonly made into black enamelled leather, for ladies' 
shoes and boots, and the stouter varieties are used for the 
uppers of hunting and riding boots, knapsacks, &c. Seal 
skins are frequently merely dressed, with the fur on, for 
ladies' jackets and muffs, and various articles of clothing, 
as waistcoats, caps, &c. 

Deer Skins are much used for making gloves and cha- 



42 LEATHER MANUFACTURE. 

mois leather, and are prepared by the tawing process, in 
the same manner as sheep and goat skins. The chief 
manufacture in connection with deer skins is carried on in 
the United States, and is comparatively unimportant in 
this country. 

Porpoise Skins. — These skins are now being much 
used for uppers of boots, for which purpose they are admi- 
rably suited, since, when tanned, they yield a very supple 
and durable leather. Round and flat laces prepared from 
these skins are exceedingly tough and strong. In Canada 
the skins of the white porpoise have been tanned into 
leather, which is said to be soft, strong, and of a beautiful 
finish. 

Serpent and Crocodile Skins. — During the past few 
years specimens of tanned serpent skins have entered the 
market, as also those of the crocodile and alligator, and 
at the period at which we are writing, reticules, purses, 
and bags formed of crocodile and alligator skins are freely 
exposed for sale. Indeed, so great is the demand for this 
variety of ornamental leather that close imitations of the 
various skins are produced by means of the electrotype 
process. (See page 432.) 



CHAPTER IV. 

TANNIN OR TANNIC ACID. 

Tannin or Tannic Acid. — Preparation of Tannic Acid. Pelouze's Process 
— Berzelius' Process. — Bouillon-Legrange's Process. — Merat-Guillot's 
Process. — Dize's Process. — Deyeux's Process. — Proust's Process. — 
Serturner's Process. — Schering's Process. — Badvil and Lienders' 
Process. — MM. Coez's Process. — Kohlrausch's Process. — Properties 
of Tannic Acid. — Parnell's Views. — Pure Tannic Acid. — Reactions 
of Tannic Acid. — Table of the Percentage of Tannin in Vegetable 
Substances. — Morfit's Observations. — Artificial Tannin. 

Tannin, or Tannic Acid. — This powerful astringent 
vegetable principle, which is also known by the names of 
Tan and GaUo-tannic acid, exists in those excrescences called 
Gall nuts, which are found upon certain varieties of oak, 
and some other plants, as the Tamarisk. It also occurs in 
a great number of trees and plants. Galls are formed by 
the female of the insect Cynips (or Diplolepsis) Gallce tinc- 
torum, piercing the buds of a species of oak named Querents 
infectoria, and there depositing its eggs. These producing 
irritation, cause the juices of the plant to flow towards 
the wound, and the subsequent enlargement of the part, 
in the form of a vegetable tumour, or gall, round the 
larva. This grub, when fully developed, escapes by a 
hole which it perforates in the gall. The Quercus infectoria. 
is the principal species of oak which yields the nut-galls of 
commerce. 

Preparation of Tannic Acid, Pelouze's Process. — 
By this process, tannic acid is obtained by means of a per- 
colator, a (Fig. 2) fitted into a receiver b. The percolator 
is a cylindrical glass vessel, open at both ends, the upper 
opening being fitted with an air-tight stopper, anr* the 



44 



LEATHER MANUFACTURE. 



lower end adjusted to the neck of the glass receiver b. 
The upper vessel, or percolator, is about half filled with 
coarsely-powdered galls, which are prevented from falling 
through the lower opening by a plug of 
cotton, and the powder is then covered, in 
successive portions, with ether, which has 
been previously shaken up with a little 
water.* The stopper is now inserted in 
the mouth of the percolator, and the mix- 
ture allowed to digest for several hours, 
after which the stopper is withdrawn, 
and the liquid allowed to filter into the 
receiver beneath. "When all the liquid 
has passed through, the powdered galls 
are washed with more ether introduced at 
the top as before. After standing for a 
short time, the filtered liquor will be found 
to separate into two distinct strata, of 
unequal density. The tannic acid and 
gallic acid, being both extracted by the 
mixture of ether and water, now sepa- 
rate ; the lower stratum being a solu- 
tion of tannin (generally of an amber 
colour) in water, and the upper stratum an 
etherial solution of other substances con- 
tained in the galls, the most important 
of which is Gallic acid. The two solutions are next sepa- 
rated; the aqueous solution of tannin is gently evapo- 
rated to dryness and finally exposed to an oven heat, 
at a temperature not exceeding 212° Fahr. The result is 
an amorphous, or uncrystallised mass of tannin, nearly if 
not quite pure, the yield being frequently about 40 to 45 
per cent, of the weight of galls used. The ether in the 
lighter liquid is recovered by distillation, over a water 
bath, with the aid of a Liebig's condenser, supplied with 
ice-cold water. 

Berzelius' Process. — A hot infusion of galls is first 

* It is absolutely necessary that the ether should he agitated with 
water, otherwise not a fraction of tannin will he obtained. 




Fig. 2. 



TANNIN OR TANNIC ACID. 45 

obtained, and to this is added a few drops of sulphuric acid. 
The mixture is to be well agitated, then filtered, and to 
the filtered liquid sulphuric acid, diluted with its own 
weight of water, is added gradually, until the precipitate 
formed, after standing for an hour, is found in the form of a 
semi-fluid gelatinous mass. The liquid is then decanted 
and carefully mixed with concentrated sulphuric acid so 
long as a precipitate forms. The precipitate is then 
washed with water strongly acidulated with sulphuric acid, 
and is then pressed between the folds of bibulous (filtering) 
paper. The precipitate is next dissolved in pure water, 
and to the solution carbonate of lead, in very fine powder, is 
added, and after agitation and maceration for some time, 
until the sulpho-tannate is all decomposed, the mixture is 
again filtered, and the liquid gently evaporated to dryness. 
The residuum is finally powdered and digested in ether, 
which is now allowed to evaporate spontaneously, and the 
resulting powder is at once bottled to preserve it from 
the air. 

Bouillon-Legrange's Process. — By this method, an in- 
fusion of nut-galls is precipitated by carbonate of am- 
monia. The precipitate is afterwards washed with cold 
water, and then digested repeatedly in fresh quantities of 
alcohol at - 817. This process, however, does not yield 
pure tannin. 

Merat-Guillot's Process. — An infusion of nut-galls is 
precipitated by lime water, and the precipitate treated with 
dilute nitric or hydrochloric acid. Effervescence occurs, 
and the liquor assumes a dark brown colour. After filtra- 
tion, a bright black substance separates, which the inventor 
assumes to be pure tannin, but according to Sir H. Davy 
it is combined with vegetable extractive and a certain 
portion of lime. 

Dize^s Process. — This process consists in pouring con- 
centrated sulphuric or hydrochloric acid into a concen- 
trated infusion of nut-galls, when a white precipitate is 
produced, which Proust believes to be a combination of 
tannin with the acid employed. It is purified by washing 
with cold water, then dissolved in warm water, and the 



46 LEATHER MANUFACTURE. 

acid is saturated with, carbonate of potash. This process 
does not produce pure tannin, but a substance in which 
both gallic acid and extractive are present. 

Deyeux's Process. — By this method, a strong infusion 
of galls is precipitated with a concentrated solution of 
carbonate of potash, when an abundant yellowish- white 
precipitate is formed, which on drying yields a whitish 
powder. The product, however, is not pure, as proved by 
Davy and Tromsdorff, who found it to be a combination of 
tannin, gallic acid, carbonate of potash, and lime. 

Proust's Process — To an infusion of nut-galls is 
added a solution of chloride of tin until the precipitate of 
tannate of tin ceases to fall. A yellowish-white precipitate 
is formed, which is afterwards washed and mixed with 
cold water. A current of sulphuretted hydrogen gas is 
then passed through the product, which, is next filtered 
and then evaporated to dryness. Although a tolerably 
pure product is obtained, the presence of gallic and 
hydrochloric acids and extractive in small quantities have 
been traced. 

Serturner's Process. — By this process an alcoholic 
inf vision of nut-galls is precipitated by warm carbonate of 
potash. After decanting the liquid, the residue is washed 
with alcohol, and then treated with sulphuric acid. This 
is then evaporated, and the residue treated with alcohol. 
The excess of sulphuric acid is precipitated by carbonate 
of lime. After filtering, the filtrate is evaporated to 
dryness, when tannin containing very little gallic acid is 
the result. 

Schering's Process. — This is called, by the patentee, 
the "manufacture of improved tannic acid." The thick 
extract, or solution of tannin, whether it be combined 
with water, alcohol, or ether (!) is placed in a heated 
chamber, the heat being maintained and regulated at a low 
temperature, and the air excluded as far as possible. The 
extract or solution is thus slowly evaporated, until it is 
reduced to a thick pasty condition. It is then forced by 
a pressing apparatus through a plate perforated with small 
holes, from which it exudes in thin filaments, like thin 



TANNIN OR TANNIC ACID. 47 

vermicelli threads ; these are wound, as they exude, on 
suitable reels, or cylinders, or they may be collected in any 
convenient manner. The threads so obtained, on cooling, 
are very brittle, and will break up into golden, shining, 
needle-like fragments, which can be readily collected, and 
preserved in bottles. 

Badvil and Lienders' Process. — The object of this 
invention is to obtain "tanning material from the asphodel 
plant," and is based upon the discovery that this plant 
contains tannin which does not dissolve under the influence 
of acids and fermentation, and which is not assimilable, 
being diffused or mixed with a large proportion of water, 
saccharine matter, and other substances. To render the 
tannin " adaptable for leather dressing like the best 
sumacs, it is necessary to eliminate the main portion of 
the water and saccharine matter." For this purpose the 
asphodel is washed, to free it from the earth which may 
adhere to it ; it is then grated or crushed to break up the 
cells, and the pulp thus obtained is then pressed. The 
juice which flows from it is subjected to a complete fer- 
mentation, to extract its alcohol. The pressed pulp, which 
contains nearly all the tannin, is dried, preferably by 
exposure to the sun, and finally reduced to a powder or 
extract. " It can be used in this state for leather-dressing 
purposes." 

MM. Coez's Process. — The tanning matter or juices 
being extracted by the usual processes, the decoctions are 
placed in wooden vessels, in which they are intimately 
subjected to the process of decoloration in the following 
manner : — Oxalic acid is first added in the proportion of 
one grain of acid to every 100 litres * of juice, the density 
of which is unimportant, for the purpose of saturating the 
lime which is contained in the water used in the process of 
extraction, in proportions varying according to the quality 
of the said water. After allowing a few minutes for the 
oxalic acid to act, gelatinous alumina is introduced in the 
proportion of about 250 grains per 100 litres of juice, and 

* 1 litre is equal to 34 fluid ounces nearly, or about six ounces less than 
an Imperial quart. 



4 8 LEATHER MANUFACTURE. 

per degree of the density. The materials are now vigorously 
agitated, and the mixture being immediately filtered, the 
alumina remains upon the filter with the colouring matter. 
The clear tannic liquid, from which the colouring matter 
has thus been removed, is collected and evaporated in vacuo 
by known means, and brought to a density of about 20° 
Baume. The tannic extract obtained by this process is said 
to be remarkably pure, is soluble, and readily assimilable 
by hides or skins. 

Kohlrausch's Process. — This process, which is also 
applicable to the extraction of colouring matters from dye- 
woods, consists in first reducing the wood or bark by cleav- 
ing, breaking, sawing, &c, to small pieces about \ inch to 
3 inches long, about the same width, and from -£$ to \ inch 
thick. These pieces are placed in closed vessels of 
copper or enamelled iron, and treated with water at about 
20 to 75 0. (68° to 167° F.), under pressure, so as to ex- 
tract tannic acid, &c, the different vessels forming a 
"continuous working battery," and being connected with 
each other by pipes, which may be heated if desired. If, 
for instance, the " battery" consists of twelve vessels, pure 
water, under pressure, is allowed to enter the first vessel, 
where the process begins, and is continued until the den- 
sities of the liquids inside and outside the bark-cells are 
equalised. The liquid is afterwards allowed to pass from 
the first into the second vessel, where the tannic acid 
solution will become more concentrated. From the second 
vessel the liquid passes into the third, and so on up to the 
eleventh vessel, where the concentration of the liquid is 
almost equal to that in the cells containing the raw 
materials. During that time, pure water has been supplied 
to the first vessel, by which its contents become exhausted 
and may be discharged. Pure water is now admitted to 
the second vessel, and the twelfth filled with raw material. 
The extracted liquid is afterwards made to pass into the 
twelfth vessel, the first filled with raw material, the second 
discharged, and pure water allowed to flow into the third 
vessel, and so on, in such a manner that the contents of ten 



TANNIN OR TANNIC ACID. 49 

vessels are continuously subjected to dialysis* The 
necessary temperature of the water may be maintained by 
providing the connecting pipes with heaters of any suitable 
construction. The extract obtained by this process may be 
further concentrated in vacuum pans, or may be employed 
directly for the manufacture of leather. 

Properties of Tannic Acid. — This acid, as it exists in 
different vegetables, varies in its chemical reactions, some- 
times in a very marked degree. According to Gmelin, 
the following plants contain the modification of tannin 
which renders solutions of peroxide of iron (as the persul- 
phate of iron for example) a deep blue : — Galls, the roots of 
Lithrum salicaria, Geum urbanum, and rivale, Potentilla 
argentea and anserina, Arctium lappa, Sanguisorba officinalis, 
Poterium sanguisorba, Alchemilla vulgaris, Polygonum bistorta, 
Iris pseudacorus, Nymphcea alba, the wood of the oak, and 
many other trees, the bark of different species of oak, the 
leaves of oak, Uva ursi, and many others, the twigs of the 
black currant and sumac, the petals of pomegranate, Rosa 
gallica and Pceonia officinalis. The tannin which gives a 
green precipitate with persalts of iron is found in Catechu 
and Kino, in the roots of the Tormentilla erecta, Potentilla 
reptans, Rosa canina, Rheum rhaponticum, &c, in the diffe- 
rent species of Cinchona bark, in Cinnamon, Cassia, and in 
horse-chestnut bark; in the leaves of Salvia officinalis, 
Lamium album, Glecoma hederacea, &c, in the varieties of 
tea ; in the flowers of Tilia JEuropeea, Centaur ia cyanus, and 
Arnica montana; in horse-chestnuts, date-stones, &c. 

* In practical chemistry, the method of separating substances by " diffu- 
sion," through a hoop covered with parchment paper, is called dialysis. 
When a solution having a higher specific gravity is introduced into a 
cylindrical glass vessel, and water then very cautiously poured into it in 
such a way that the two layers of liquid remain unmoved, the substance 
dissolved in the lower liquid will gradually pass into the supernatant 
water, though the vessel may have been left undisturbed, and the tempera- 
ture remain unchanged. The gradual passage of a dissolved substance 
Irom its original solution into pure water takes place notwithstanding the 
higher specific gravity of the substance which opposes this passage ; this 
is called "diffusion of liquids," the investigation of which was due to 
the late Professor Graham, of the Royal Mint, 



50 LEATHER MANUFACTURE. 

According to the experiments of Berzelius and others, 
the tannin in all plants is essentially the' same substance, 
the different colours of the various precipitates with per- 
salts of iron depending on the accidental presence of 
impurities, and also on the nature of the salt of iron used. 
But the more recent researches of Dr. Stenhouse favour 
the conclusion that not only must the tannins of different 
plants which produce different coloured precipitates in 
the same solution of peroxide of iron be regarded as 
distinct substances, but even that some of the varieties 
of tannin which agree in their reaction upon salts of 
iron, and in their general chemical habitudes, are by 
no means identical.* Dr. Stenhouse availed himself of 
a new test for tannin, which affords indications only with 
the variety of tannin contained in galls, and with gallic 
acid, which consists in the production of pyrogallic acid, 
when the body to be tested is subjected to destructive 
distillation: pyrogallic acid is disengaged as a crystalline 
sublimate. 

Farnell's Views. — This chemist observes : " Although 
the astringent matter contained in several vegetables is 
designated by the same name, tannin, or tannic acid, yet 
all these bodies do not appear to be identical. The differ- 
ences, however, which are perceptible in the properties of 
most of the substances which are thus classed together 
are small, and seemingly of no great importance in the 
practical application of this vegetable principle. Other 
vegetable matters exist, the properties of which amply 
distinguish them from tannin. The most characteristic 
properties of tannin are, astringency in taste, and the 
power of being precipitated from its aqueous solution, 
either of a bluish-black, or dark green colour, by a 
solution of the peroxide of iron, and of a dirty white, or 

* It is now generally recognised that although the numerous varieties 
of tannin all possess the common property of precipitating gelatine, not 
only do they differ greatly in their chemical reactions, hut the leather 
produced from them is of very varied character — sometimes of very indiffe- 
rent quality; and were it not for the custom of mixing certain tanning 
materials with others of known excellence, it is douhtful whether some of 
them would not he altogether abandoned. 



TANNIN OR TANNIC ACID. 5! 

brown colour, by a solution of gelatine. The precipitate 
produced in a solution of a persalt of iron, which is the 
tannate of peroxide of iron, is the basis of common writing 
ink. A solution of protomlphate of iron [copperas), per- 
fectly free from all peroxide of iron, experiences no 
immediate change on the addition of tannin; but the 
mixture instantly becomes deep blue or black on exposure 
to the air, through the absorption of oxygen, and forma- 
tion of peroxide of iron. If cold aqueous solutions of 
tannin and animal gelatine (glue, bone- size or isinglass), 
are mixed in certain proportions, both of these bodies are 
almost completely thrown down as a precipitate, known by 
the name of tanno- gelatine, which generally contains about 
half its weight of tannin. Sometimes, particularly when 
heat is applied, or when the acid is in excess, the pre- 
cipitate forms, on stirring, a very viscid and elastic mass, 
somewhat resembling caoutchouc. In its chemical condi- 
tion, tanno- gelatine is quite analogous to leather, and was 
at one time, in fact, generally regarded as that substance 
in a pure state. This cannot be the case, however, as 
gelatine does not exist ready formed in the skin (according 
to Berzelius) and tanno- gelatine, unlike leather, is slightly 
soluble in water at the boiling point. The aqueous 
solution becomes turbid on cooling, owing to the re-pre- 
cipitation of the tanno-gelatine. This compound may 
also be dissolved by an excess of a solution of gelatine, 
but not by an excess of a cold solution of tannin. When 
dried, it loses its viscidity and elasticity, and becomes 
brittle and pulverulent." 

Pure Tannic Acid is nearly colourless, inodorous, pre- 
eminently astringent in taste, uncrystallisable, very soluble 
in water, and less soluble in pure alcohol and ether. Its 
aqueous solution reddens litmus, and decomposes the 
alkaline carbonates, with effervescence. It combines 
energetically with gelatine ; when, therefore, a piece of 
skin or bladder is immersed, in its aqueous solution, the 
tannic acid is entirely abstracted ; whereas, if gallic acid 
were present, that acid remains dissolved in the water. 
Tannic acid also furnishes an abundant white precipitate 



52 LEATHER MANUFACTURE. 

in solutions of isinglass or glue. A concentrated aqueous 
solution of tannic acid is precipitated by hydrochloric, 
nitric, sulphuric, phosphoric, and arsenic acid ; but not 
by oxalic, tartaric, lactic, acetic or citric acid. By the 
prolonged action of acids and alkalies, tannic acid under- 
goes various, and often complicated, changes, amongst 
which its conversion into gallic acid is the most common. 
— Branch. 

By exposure to the air, a solution of tannic acid 
gradually becomes turbid, and deposits a grey crystalline 
powder, which is gallic acid. By contact with the air 
oxygen is absorbed, and an equal volume of carbonic acid 
is evolved ; only a portion of the tannic acid, however, is 
thus decomposed, and is converted into gallic and ellagic 
acids. It is the opinion of many, that the gallic acid 
present in gall nuts is due to the absorption of oxygen 
by the tannic acid, during the process of vegetation. 
And to this end, possibly, the insect which inhabits the 
gall nut during its development, may be the real active 
agent. 

Reactions of Tannic Acid. — The following reactions 
of tannic acid are given by Abel and Bloxam* : — 

Concentrated sulphuric acid, treated with (solid) tannic 
acid, produces, immediately, a dark, purplish-black liquid, 
but does not evolve carbonic oxide. 

When heated on platinum, tannic acid burns, chars, and 
emits a peculiar odour. 

Alkalies, added to a solution of tannic acid, cause it to 
absorb oxygen from the air, and to assume a brown colour. 

Sesquichloride of iron produces a bluish-black precipi- 
tate of tannate of sesquioxide of iron. 

Dilute sulphuric (or hydrochloric) acid produces, in a 
pretty concentrated solution of tannic acid, a white pre- 
cipitate, which is an insoluble compound of the two 
acids. 

Tannin is precipitated from a tolerably strong solution 
of the mineral acids, and these precipitates consist, according 

* " Handbook of Chemistry." By F. A. Abel and C. L. Bloxam. 



TANNIN OR TANNIC ACID. 



53 



to Berzelius, of compounds of tannin with the acids respec- 
tively. If the compound with sulphuric acid be boiled for a 
few minutes in dilute sulphuric acid, the tannin becomes con- 
verted into gallic acid, which is deposited in coloured 
crystals on cooling. When the sulphuric acid employed 
for this purpose is diluted with 7 or 8 times its bulk of 
water, the crystals of gallic acid are colourless and nearly 
pure. A similar change occurs according to Liebig where 
the compound of tannin and sulphuric acid is boiled with 
an excess of caustic alkali ; and the action of hydrochloric 
acid on, tannin is quite the same as that of sulphuric acid. — 
(Stenhouse.) In these cases of the conversion of tannin into 
gallic acid, the action of the air is unnecessary. 

Table of the Pekcentage of Tannin in Vegetable Substances. 



Substance. 



Per Centage 
of Tannin. 



Catechu, Bombay 55 - 

„ „ light colour 26-3 

„ Bengal 44-0 

„ Peru, dark brown colour . . 46- 8 

Ehatany root 42 - 6 

„ 38-3 

Kino — Tannin and Extractive 75*0 

Butea Gum 73"2 

Nut Galls, Aleppo 70-0 

,, Chinese 74-0 

,, Istrian 24-0 

Old Oak, white inner hark 21*0 

14-2 

Young Oak, white inner bark 15 - 2 

„ coloured, or middle bark 4 - 

„ entire bark 6 - 

,, spring-cut bark 22 - 

Oak, Kermes, bark of the root 8 - 9 

„ 100 years old 8*5 

„ young 13-8 

,, British 50 years old 8-9 

„ Coppice 12 - 5 

„ Irish 45 years old 9-50 

„ Belgian 8-3 

Terra Japonica, or Gambier 44'0 

Avens root, Geum urbanum 41 - 

Squill, bulb 24-0 

Statice of South Carolina 124 



Authority. 

Davy. 
Mulligan. 



Peschier. 
Gmelin. 
A r auquelin. 
E. Solly. 
Crookes. 



Rhodes. 

Cadet de Gassincourt. 

Davy. 



Davy and Geiger. 

Davy. 

Davy and Geiger. 

Muller. 

>) 
Mulligan and Downing. 



Eisenbeck. 
Tromsdorff. 
Vogel. 
Parrish. 



54 



LEATHER MANUFACTURE. 



Substance. Pe f r ,£entage 

of Tannin. 

Birch bark 1-6 . 

14 . 

Beech bark 2-0 . 

Larch bark 1 -G . 

Hazel bark 3-0 . 

Chestnut, American rose 8 

„ Carolina 6-0 

,, French 4-0 . 

„ Spanish, white inner burk 1*3 
„ ,, coloured or middle 

bark 03 . 

,, ,, entire bark 0-5 

,, horse 2-0 

Lombardy Poplar 3' 5 

Blackthorn 3-3 . 

Ash bark 33 

Sassafras, bark of the root 58-0 

Elm bark 2-9 . 

Sumac, Sicily 24 - 

,, Malaga 16*4 

„. 10-4 .. 

, , Carolina 5-0 

,, A^irginia 27'0 

„ 19-5 . 

Willow, Leicester, Avhite inner bark 16 - 
,, ,, coloured or middle 

bark 3-0 . 

,, ,, entire bark G - 8 

„ 3-9 . 

,, ,, bark of the trunk 1-4 

,, weeping 16 - 

Sycamore bark 16-0 

,, I"* • 

Elder 2-3 . 

Plum tree 1 - 6 

Cherry tree 24-0 . , 

,, ,, Cornish 19-0 . 

Tormentilroot 46 - 

Comus sangninea of Canada 44*0 

Alder bark 36-0 .. 

Hemlock 139 .. 

Dividivi 50-0 .. 

49-2 

Valonia 34-7 . . 

Myrobalans 35 "0 

Mimosa bark 17'8 .. 

„ „ 31-1 .. 

Apricot bark 32 - . . 

Pomegranate 32*0 . , 

Bohemian olive 14 - . . 



Authority. 



Davy. 

Biggers. 

Davy. 



Cadet de Gassincourt. 

De Fontenelle. 
Davy. 



De Fontenelle. 

Davy. 

Reinsch. 
Davy 

Crookes. 

Davy. 

Franck. 

Cadet de Gassincourt. 

Anon. 

Muller. 

Daw. 



Mulligan and Downing. 

Biggers. 

Cadet de Gassincourt. 

)> 
Biggers. 
Davy. 
Biggers. 
Cadet de Gassincourt. 



Mulligan and Downing. 

Crookes. 

Muller. 

Mulligan and Downing. 

Crookes. 

Mulligan and Downing. 

Muller. 

De Gassincourt. 



TANNIN OR TANNIC ACID. 55 

Substance. ^T^Sf Authority. 

Tan shrub, with myrtle leaves ..... . 13 - .. De Gassincourt. 

Service tree, bare, June berry 18-0 .. ,, 

Cloves 15-0 .. Davy. 

Winter's bark 9-0 . . Henry. 

The more recent methods of estimating tannin which 
have been introduced since the foregoing determinations 
were arrived at, render it advisable that the percentage 
in this Table should be received with caution ; at the 
same time it must be admitted (owing to the difference 
which exists between tannins obtained from different 
sources), that even the more modern determinations of 
this substance are not wholly reliable. 

Morfit's Observations. — 1. That tannin is never found 
to any extent in the interior of the trunk of trees. 2. That 
it does not exist in poisonous plants, nor in those with a 
milky or viscid sap. 3. That its proportion is greater in 
young than in old. plants. 4. That the tannin is converted 
into bitter principle, as the plant increases in age. 5. That 
it is most abundant in the cortical layers of the bark, and 
is usually absent altogether in the epidermis. 6. That the 
proportion of tannin in bark varies with the season, de- 
creasing as the severity of the winter increases, and 7. 
That the two extremes of the quantity are attained in winter 
and spring. 

Artificial Tannin. — According to Hatchett,* a substance 
having some of the characteristics of tannin, and to which 
the name artificial tannin has been given, may be formed 
by digesting charcoal in dilute nitric acid for several days. 
The charcoal is at length dissolved, and a reddish-brown 
liquor is obtained, which yields, after careful evaporation, 
a brown glossy substance, amounting to about 120 parts, 
from 100 parts of charcoal. This artifical tannin differs 
in one particular from natural tannin, namely, that it resists 
the action of nitric acid, which decomposes all varieties of 
natural tannin, though some are more capable of resisting 
its action than others. Artificial tannin has a somewhat 

* Philosophical Transactions, 1805-6. 



5& LEATHER MANUFACTURE. 

bitter, astringent taste, is soluble in water, and forms an 
insoluble precipitate in solutions of animal gelatine, con- 
sisting, according to Hatchett, of 

Artificial tannin 36 

Gelatine 64 

100 

Hydrochloric and sulphuric acids produce brown precipi- 
tates in solutions of artificial tannin, which are soluble in 
hot water. A variety of artificial tannin may be formed by 
digesting camphor and resins in sulphuric acid, until the 
liquor becomes black, and on being poured into water 
deposits a black powder, which being digested in alcohol 
yields a brown matter, soluble in water, and which pro- 
duces an insoluble precipitate with gelatine. 



CHAPTER V. 

GALLIC A CID. 

Gallic Acid. — Preparation of Gallic Acid from Galls. — Scheele's Method.- 
Liebig's Method. — Graham's Method. — Pharmaceutical Methods.— 
Properties of Gallic Acid. — Pyrogallic Acid. — Ellagic Acid. 

Gallic Acid. — The frequency — nay almost constancy — 
with which gallic acid is associated with the great astrin- 
gent tanning principle, — tannic acid, — and the ready con- 
version of the latter into the former, by the influence of 
oxygen, renders it advisable that it should be considered 
apart from its associates, more especially since this vege- 
table acid often plays an important though an objection- 
able part in the process of tanning. Gallic acid was 
discovered by Scheele, and various methods of obtaining it 
in a pure state were afterwards devised by Deyeux, 
Braconnot, Liebig, and Dr. Stenhouse. The conversion of 
tannic acid into gallic acid by the agency of oxygen was 
first demonstrated by Pelouze ; and the existence of the 
latter acid, independent of tannic acid, in several vegetables, 
has been proved both by Dr. Stenhouse and Robiquet. 
Since this acid, however, is almost always associated with 
tannic acid in the various plants which yield these 
substances, and moreover exists in much smaller propor- 
tions than the tanning principle — often a mere trace — it 
may not be unreasonable to infer that the existence of 
gallic acid is due to the oxidation of the tannic acid 
generated or secreted by plants, and that it is not formed 
in nature as a separate and distinct substance. This view 
is supported by the readiness with which tannic acid com- 
bines with oxygen, when exposed to the air under certain 



58 LEATHER MANUFACTURE. 

conditions, as we find when considering its mode of prepa- 
ration from gall nuts. 

Preparation of Gallic Acid from Galls. — The process 
recommended by Dumas is as follows : A quantity of nut- 
galls are reduced to powder, and this is next made into a 
paste with water ; in this state, the mass is exposed to the 
action of the air, in a warm situation, the temperature 
being from 70° to 80° Fahr., for two or three months, more 
water being added from time to time, to make up for that 
which is lost by evaporation. At the end of the above 
period, the mouldy, dark-coloured mass is strongly pressed 
in a cloth, and the solid portion boiled in a considerable 
quantity of water.* The solution is to be filtered tvhilst 
hot, and on cooling, crystals of gallic acid will deposit at 
the bottom of the vessel. These crystals are afterwards 
to be well drained, and pressed between folds of white 
blotting paper, and they are next to be purified, by boil- 
ing them with about one- sixth of their weight of pre- 
pared animal charcoal in eight parts of water. The solu- 
tion is to be again filtered whilst hot, and the clear liquor 
set aside to cool, when pure crystals of gallic acid will 
be obtained, which must be well drained and dried over a 
water-bath. 

Scheele's Method. — A filtered decoction of galls is 
exposed to the air for some months, in an open vessel ; 
after a time it grows mouldy, and becomes covered with 
a thick glutinous pellicle, or scum ; in two or three months 
the sides of the vessel, and under portion of the pellicle, 
are found to be covered with small yellow crystals of gallic 
acid, which may be purified as above. 

Liebig's Method. — To a strong aqueous solution of 
tannic acid, sulphuric acid is added so long as a precipitate 
falls ; the powder is collected, washed and dissolved by 
heat, in dilute sulphuric acid; the solution, after boiling for 
a few minutes, and then being allowed to cool, deposits 
abundant crystals of gallic acid. 

Graham's Method. — A strong infusion or decoction of 

* Gallic acid is soluble in 100 parts of cold water, and in 3 parts of 
boiling water. 



GALLIC ACID. 59 

galls is precipitated with sulphuric acid in the cold ; the 
resulting thick mass is mixed with cold dilute sulphuric 
acid, and the liquid pressed out. The " marc " is next 
treated with sulphuric acid, diluted with twice its weight 
of water, and after boiling the mixture for some minutes, 
the whole is set aside to cool ; the resulting crystals are 
purified with animal charcoal, as before. 

Pharmaceutical Methods — The Dublin Pharmacopoeia 
gives two methods of preparing gallic acid, one of which 
is based upon the process of Dumas, or Scheele, and 
the other on that of Graham or Liebig. 1. Galls, in 
coarse powder, 1 lb. ; make into a stiff paste with water, 
and place in a porcelain dish, and expose in the moistened 
condition for six weeks. The solution of the first crop of 
crystals is made in 10 fluid ounces of boiling icater, and 
then filtered. When the nitrate (the filtered liquor) has 
cooled down to 80° Fahr., it is to be poured off from the 
crystals which have formed, and the crystals are to be 
washed with ice-cold icater, 3 fluid ounces, and then drained 
and dried — first on blotting paper, and finally by steam or 
water heat. By boiling the undissolved portion of the 
galls with 45 fluid ounces of fresh water, more crystals are 
obtained. 2. One pound of powdered nut-galls are steeped 
for 24 hours in 1 pint of water, and after being placed in 
a porcelain dis23lacement apparatus, are treated with one 
and a half pint of water, added in successive portions ; 5 
fluid ounces of oil of vitriol, diluted with an equal bulk 
of water and allowed to cool, is then added to the perco- 
lated infusion, and when thoroughly mixed, the liquid is 
filtered from the precipitate which forms. Oil of vitriol 
5 fluid ounces diluted with an equal bulk of water as 
before, is now added to the filtrate ; the precipitates, 
enveloped in calico, are submitted to powerful pressure, 
and subsequently dissolved in a solution composed of oil 
of vitriol 16 fluid ounces, and water 56 fluid ounces. The 
solution is then boiled for 20 minutes, and set aside for a 
week, at the end of which time the deposit which forms is 
dissolved in three times its weight of boiling water, and the 
solution treated as before. 



6o LEATHER MANUFACTURE. 

Properties of Gallic Acid. — Pure gallic acid assumes 

the form of white or nearly colourless feathery crystals of 
a beautiful silky lustre ; the commercial acid, however, is 
usually of a pale yellow colour ; it is soluble in alcohol, and 
also, sparingly, in ether ; its solution in water undergoes 
decomposition when exposed to the air. When strongly 
heated, gallic acid is converted into meta- gallic acid, or 
into pyrogallic acid, according to the way in which the 
heat is applied. Gallic acid is distinguished from tannic 
acid by not precipitating gelatine from its solution,* and 
by not affecting the proto-salts of iron (as proto- sulphate of 
iron, for example), and by giving a deep bluish-black pre- 
cipitate with sesqui or per salts of iron (as persulphate of 
iron) which disappears when the liquor is heated. It is 
distinguished from pyrogallic acid by its inferior solubility 
in water. If, in a mixed solution of gallic acid and tannic 
acid, a piece of depilated skin be immersed for some time, 
the whole of the tannin will be absorbed by the skin, leav- 
ing the unaltered gallic acid in solution. 

Gallic acid is useless for tanning purposes, therefore it is 
of considerable importance to prevent, as far as possible, 
the conversion of the tannin contained in the tanning liquors 
into gallic acid — a change that is more likely to occur 
when ooze or infusion of the astringent matter is used, 
than when ground bark and water only is employed, as in 
the old tanning process. When tanning solutions undergo 
decomposition, a considerable percentage of tannin is con- 
verted into gallic acid and other modifications of tannic 
acid, by which a positive loss of tanning power is sus- 
tained. The tannin from galls and sumac is very liable 
to undergo this change, in consequence, probably, of the 
insoluble matters acting as a ferment, and thereby pro- 
moting the conversion of tannin into gallic acid.f This 
subject will be further considered when treating of gallic 
fermentation. 

Although gallic acid possesses no tanning property, its 

* Pure gallic acid will not throw down a precipitate from a solution of 
isinglass. 

t Parnell thinks that the malic acid existing in sumac leaves is the 
cause of the rapid fermentation of sumac liquors. 



GALLIC ACID. 61 

existence in spent or exhausted tan liquors is sometimes 
taken advantage of to swell the hides after they have been 
limed in the usual way, instead of employing dilute 
sulphuric acid, by which the absorption of the tannin is 
promoted. 

Besides being present ready formed in galls and sumac, 
gallic acid occurs in some other vegetables ; it is said to be 
found in the seeds of the mango-tree, in divi divi, valonia, 
black and green teas and myrabolams. 

Pyrogallic Acid. — When gallic acid is subjected to dry 
disfflJation, at a temperature between 410° and 420° Fahr., 
a white crystalline substance distils over, which is pyrogallic 
acid. Its preparation, according to the method suggested 
by Dr. Stenhouse, is as follows : — Finely powdered galls 
are treated with successive portions of cold water till ex- 
hausted, and the infusions carefully evaporated to dryness, 
when they leave a spongy, deliquescent (that is, capable of 
absorbing the moisture from the air) mass, which is to be pul- 
verised and spread equally over the bottom of a cast-iron pan, 
3 or 4 inches deep, and about a foot in diameter, the top of 
which is covered with a diaphragm of bibulous paper (filter- 
ing paper) pasted round its rim, pierced with pin holes, and 
surmounted by a paper cap 12 to 18 inches high. The pan 
is then cautiously heated for 10 or 12 hours, over an oil- 
bath, so as to preserve its temperature as nearly as possible 
at about 400° Fahr.* The crystals of sublimed pyrogallic 
acid collect in the cap, and the other products are chiefly 
absorbed and retained by the paper diaphragm. 

Pyrogallic acid is white, crystalline, without odour, and 

of a bitter taste. When pure it does not redden litmus 

paper ; it is very soluble in water, ether and alcohol. This 

acid has been much used in photography, its application 

having been first suggested by the author's late friend, Mr. 

Frederick Scott Archer — the inventor of the well-known 

" collodion process." 

* If the heat of the bath be rapidly increased, and the oil allowed to 
boil, carbonic acid will be given off, instead of the crystalline sublimate, 
water will distil over, and a brilliant black mass left behind, wbich has 
been called, by Pelouze, Metagallic acid, a tasteless, insoluble substance, 
resembling carbon, but nevertheless a true acid. 



62 LEATHER MANUFACTURE. 

Ellagic Acid. — This name, which is derived from the 
word galle, read backwards, was given by Braconnot to a 
substance formed along with gallic acid when moistened 
galls are exposed for some time to the air. Its existence 
was first noticed by Chevreul. According to Grischow, 
ellagic acid exists in the root of Tormentilla erecta. Being 
insoluble in boiling water, it remains after the gallic acid 
has been extracted, and may be dissolved out of the residue 
by a very weak solution of potash. If dilute hydrochloric 
acid be now added to this solution, a brownish precipitate 
is formed, which is ellagic acid, a tasteless substance almost 
insoluble in water, alcohol, and ether. It slightly reddens 
litmus paper. The bloom which appears upon the surface 
of tanned skins or hides, is ellagic acid. 

Besides the above acids, there are numerous other deri- 
vatives of tannin, which, however interesting in themselves, 
are of no importance to the tanner, and therefore need not 
be dwelt upon in these pages. 



CHAPTER VI. 
GALLIC FERMENTATION. 

Checking or Preventing Gallic Fermentation. 

It being an established fact that tannic acid, under the 
influence of moisture and atmospheric air, becomes con- 
verted into gallic acid, it will readily be understood that 
tan liquors, which are constantly exposed to the air, will 
naturally be susceptible of this change, and, as a conse- 
quence, a portion of their active princij)le (tannin) must 
in course of time suffer decomposition. Apart from this, 
however, & fermentative process takes place in the liquors, 
by which a considerable proportion of the active principle 
is converted into gallic acid ; this is denominated gallic 
fermentation, and has been a constant source of trouble and 
loss to the tanner. According to the researches of Larocque, 
the peculiar ferment of nut galls which operates the 
change, also converts sugar into alcohol and carbonic acid, 
in the same way that yeast does, whilst beer yeast, mus- 
cular flesh, and caseous matter (the solid matter of milk) 
change tannin into gallic acid. Hence gallic and vinous 
fermentation are considered to be nearly identical. 

According to Wackenroder and Larocque, it appears 
that the formation of gallic acid from tannin is consider- 
ably expedited by the contact of the insoluble vegetable 
matters which remain after the extraction of the tannin, 
at least in the case of nut-galls, and probably in that of 
all vegetable matters containing tannin susceptible of this 
change by exposure to the air. Larocque found that all 
the tannin contained in an aqueous solution of that sub- 
stance, to which was added the residue of the preparation 



64 LEATHER MANUFACTURE. 

of tannin from gall nuts by means of ether, became entirely 
converted into gallic acid, although in a closed vessel ; 
while a strong solution of pure tannin, freely exposed to 
the air during the same length of time, contained nearly 
the whole of the tannin unaltered. It is therefore con- 
cluded that the insoluble residue of the nut-galls contains a 
substance capable of acting on tannin as a ferment, and 
that the change of tannin into gallic acid in such cases is 
a species of fermentation. This is rendered still more 
probable, from the circumstance that the vinous fermenta- 
tion may be excited in grape sugar by powdered nut-galls 
which have been digested in ether; and also that contact 
with yeast, blood and albumen, produced the same effect 
on tannin as contact with the residue of nut-galls, though 
not with the same rapidity as the latter. The gallic acid 
formed from the tannin of nut-galls, through the agency 
of yeast, is mixed with a quantity of a brown bitter sub- 
stance. 

Is it not probable that while tannin exists in its natural 
proportion in the tanning infusions, that it prevents the 
fermentative decomposition to which the vegetable matters 
would be susceptible when free from it, and that when, in 
the ordinary process of tanning, the skins have removed, 
by absorption, a considerable portion of the astringent 
principle, the vegetable matter then undergoes decompo- 
sition, or incipient fermentation, which, when once set in, 
proceeds with increasing activity ? We are induced to 
offer this suggestion because we believe that, while tannin 
exists in due proportions in solution with the vegetable 
matters derived from the plant, gallic fermentation does 
not take place, but that when this proportion becomes 
reduced — either by the action of the oxygen of the air, 
or by absorption of tannin by the hides — fermentation 
supervenes. 

Checking or Preventing Gallic Fermentation. — 
Labaroque has observed that the fermentative decompo- 
sition of tannin may be prevented or checked by all the 
antiseptic substances which arrest vinous fermentation, 
such as aromatic substances and volatile oils, and soluble 



GALLIC FERMENTATION. 65 

salts of mercury. Corrosive sublimate is said to prevent 
the decomposition most effectually. According to the 
same authority, the presence of atmospheric air is not 
essential to the conversion of tannin into gallic acid, and 
no appreciable quantity of gas is liberated during the 
decomposition. 

It has been proved that dilute sulphuric and hydro- 
chloric acids speedily convert tannin into gallic acid 
without contact of the air, when the mixture is exposed 
to a moderate heat; and it has been demonstrated by 
M. Afftoine that the decomposition of tannin, when 
exposed to the air, is not at all accelerated, but rather 
retarded, by the presence of a very minute quantity of 
either of the above acids, provided the mixtures be kept at 
the ordinary temperature. Pyroligneous acid possesses 
the property of retarding the decomposition of tannin to 
a very considerable extent, probably owing in a great 
measure to the presence of empyreumatic bodies. On 
the contrary, tartaric and malic acids, and vegetable acids 
in general, accelerate the decomposition of tannin. The 
rapidity with which sumac ferments may be referred in a 
great degree to the presence of a considerable quantity 
of malic acid in the leaves, according to some analyses. — 
Parnell. 

" From the preceding observations," saj^s the same 
author, "may be inferred some of those conditions which 
the tanner should endeavour to avoid or obtain, in order 
to retard, as much as possible, the conversion of the tan- 
ning principle into gallic acid, the latter being incapable 
of combining with gelatinous tissue. Though the obser- 
vations refer particularly to the tannin of gall nuts, which 
is believed to be the same kind as that of sumac, yet 
there is every reason to believe that they are applicable to 
all vegetable substances which contain a variety of tannin, 
not even excepting those the tannin of which is not con- 
vertible into gallic acid ; for all kinds of tannin are sub- 
ject to a fermentative decomposition, though the different 
varieties may afford very different products, and, in all 
probability, the same agents which possess the power of 

F 



66 LEATHER MANUFACTURE. 

restraining the fermentation of one variety would that of 
another. An idea prevails amongst some tanners, how- 
ever, that gallic acid exerts some beneficial action or other 
in the process of tanning. This we certainly admit, pro- 
vided the ordinary process is followed ; but undoubtedly 
it is at the expense of a far more valuable and important 
agent." 

As to the part which gallic acid performs in the process 
of tanning, since it is well known that it does not enter 
into the substance of the skin, so as to form a constituent 
of the leather, we may take it that its functions are of a 
secondary character, merely aiding the absorption of the 
tannin by swelling the pores of the skin, in the same way, 
and to about the same extent, as dilute sulphuric acid. 
If, however, the hides, after liming, have been raised by 
the dilute mineral acid, it is difficult to conceive that 
gallic acid performs any useful part in the operation of 
tanning. If it could be shown that this acid assisted in 
promoting the combination of vegetable extractive with 
the substance of the skin, its importance as a constituent 
of tanning infusions would be readily understood and 
appreciated, and indeed it may be possible that in some 
way not yet understood such is really the case. 

Knowing that the oxygen of the atmosphere readily 
converts the tannin of tanning infusions into gallic acid,* 
may we not conclude that the process of handling favours 
this chemical change ? The skins, while supersaturated 
with tan liquor, are repeatedly exposed to the air, and 
the liquor which attaches to them, as also that which flows 
from them, after removal from the pits, necessarily ex- 
poses a very large superficial surface to the action of the 
air ; and it is not reasonable to suppose that under these 
conditions a considerable portion of the tannin is trans- 
formed into gallic acid ? If this be so, is not the process 
of handling, as at present conducted, a mistake ? 

Is not the system of suspension preferable ? Against 
this method it has been urged that after a while the tan- 
ning liquor, by remaining stagnant, suffers decomposition ; 
* Especially when other organic matters are present. 



GALLIC FERMENTATION. 67 

tliis, however, could be checked by keeping the liquor in 
gentle motion by means of a suitable agitator, by which 
the skins would be constantly exposed to fresh surfaces of 
the liquor, while at the same time it would be kept in an 
uniform condition until the whole of the tannin had 
become absorbed, when the spent liquor would be run off 
and replaced by fresh, in the usual way. The arrange- 
ments described in another place, would appear to be a 
feasible plan of treating skins in tan-liquor, and would, 
we should say, render the process of handling to a great 
extent unnecessary. 

Carbolic acid has been frequently used, with good 
effect, to check gallic fermentation ; pyroligneous acid 
(wood vinegar) has also, as we have said, been employed, 
but since its action is believed to be chiefly due to the 
empyreumatic matter Avith which it is impregnated, pro- 
bably commercial wood spirit (pyroxilic spirit), in small 
quantities, would have a similar, if not a more powerful, 
effect, since it contains a still larger quantity of empy- 
reumatic matter. We are not aware if this substance has 
been tried, but are disposed to think that a few experi- 
ments might be made with advantage. Being soluble in 
water, in all proportions, there would be no difficulty in 
applying the wood spirit ; the quantity used must be 
small, however, otherwise it will impart its natural, but 
not disagreeable, odour to the leather ; this, however, 
would probably disappear during the treatment of the 
skins in the layers. 



CHAPTER VII. 

TANNING MATERIALS. 

Sources of Tannin. — Barks. — Oak Bark. — Barking of Trees. — Nut Galls. 
— Tanning Extracts. — Catechu.— Kino. — Gambier or Terra Japonica. 
— Hemlock Extract. — Chestnut Extract. — Oakwood Extract. — Larch 
Extract. — Quebracho Extract. — Sumac. — Bhatany Boot. — Mangrove 
Extract. — Myrobalans. — Valonia. — Divi divi. — Mimosa Bark. — List 
of Tanning Materials. — Miscellaneous Tanning Materials. 

Sources of Tannin. — Since the period when Lewis, 
Deyeux, Seguin, Davy and others investigated the princi- 
ples of tanning, the vegetable kingdom has been industri- 
ously explored, and a vast number of plants examined to 
determine the presence of tannic acid and its proportion 
in the various parts of trees, shrubs, and herbs. These 
researches have not only increased our knowledge as to the 
wide diffusion of the important proximate principle, 
tannin, but have also developed new sources from which 
it can be obtained with advantage for the purposes of the 
tanner. 

The sources of tannin are classified under the following 
heads, namely — 

Barks, as of the oak, birch, mangrove, mimosa, &c. 

Boots, as of rhatany, male fern, tormentil, &c. 

Leaves, as of sumac, pomegranate, tea, &c. 

Excrescences, or gall nuts. 

Extracts, as catechu, gambier, &c. 

Flowers and Fruits. 

Seed pods. 

Barks. — One of the most important sources of tannin is 
the bark of certain trees, but more especially of the various 
species of oak, willow, hemlock and chestnut. The bark 



TANNING MATERIALS. 69 

is the rind or exterior covering of vegetables, correspond- 
ing to the skin of animals. It consists of the cuticle, or 
epidermis, the parenchyma, a cellular structure containing 
colouring matter, &c, and liber* the inner or true bark. 
This last is formed of woody fibre in great quantity, inter- 
mixed with cellular tissue. At the commencement of the 
annual growth of a tree, the bark separates spontaneously 
from the wood, in order to make room for the new matter 
forming beneath. It thus increases by yearly layers, and 
gradually perishes on the outside, owing to the distension 
from thg growth of the inner portion. Its physiological 
uses are numerous and important ; it is the depository of 
many of the secretions of plants, and it acts as a living 
filter, separating secretions from each other, and allowing 
a part of them to pass off horizontally through the medul- 
lary processes on their way to the centre of the tree. But 
the principal offices of the true bark appear to be to act as 
a protection to the tender wood, and as a channel for the 
sap in its descent from the leaves. This latter function 
directs attention to that period of the year when the sap is 
in most vigorous circulation — the spring, at which time 
the active principles deposited in the cells of the bark are 
most abundant. For example, oak bark collected in 
spring contains four times as much astringent matter as 
that collected in winter. — Coolcy. With few exceptions, 
the bark is more easily removed from a tree in spring than 
at any other period of the year. When a tree, or one of 
its branches, is cut across, the bark is easily distinguished 
from the interior layers by its colour ; and if we examine 
the bark we find that its three layers are perfectly distinct, 
and may be readily separated. 

Oak Bark. — This most important of all tanning 
materials has always been employed by British tanners 
in preference to any other ; and although large quantities 
of tanning materials from other sources are consumed in 
Great Britain, their employment is rather from necessity — 
owing to the weakness in tannin of oak bark — than from 

* So called from liber, a book, because in the early ages the inner bark 
was stripped off in layers, and formed into leaves, for writing upon. 



70 LEATHER MANUFACTURE. 

choice. Oak bark yields its tannin under the most 
favourable conditions for the gradual combination of the 
astringent matter with the tissue of the skin, and at the 
same time it parts with its extractive matter in such a 
way that by slow degrees it enters into the substance of 
the skin, and doubtless plays an important part in the 
formation of sound and durable leather. 

There are several varieties of oak, the barks of which are 
famous for their richness in tannin, amongst which may 
be named Quercus robur, Q. coccifera, Q. suber, European 
varieties ; Q.falcata, Q. rubra, Q. tinctoria, &c, indigenous 
to America. " The bark of Quercus robur — which term is 
applied to designate a group of closely -allied species or 
varieties, and of which the Q. peclunculata and Q. sessili- 
flora form the two principal — is generally preferred by 
the tanner, with the exception of Norway, the North of 
Russia, and some districts in France. In Norway the 
birch and willow are resorted to, and in Russia and France, 
the bark of other species of oak, the Quercus glomerata and 
Q. coccifera are occasionally substituted. The latter 
varietj r , known also as the kermes oak, is a tortuous, 
branching shrub, inhabiting the south of France, Portugal 
and Spain. It grows to the height of three or four feet, 
in close clumps, the roots interlacing one another, so that 
the soil, which might otherwise be washed away by the 
heavy rains, is retained. The bark of the root of this 
shrub, which is sometimes called coppice oak, is of a 
yellowish-brown hue, and very rich in tannin. It is 
much in request in France for tanning sole leather of a 
superior quality." — Muspratt. 

The common English oak (Q. robur, Linnaeus) is by 
some botanists named Q. peduncula.ta ; its acorns are 
borne on long peduncles (stems supporting the fruit), 
and is thus distinguished from Q. sessiliflora, which has 
its acorns clustered upon a very short stalk, or sessile 
(sitting), with leaves on elongated stalks. When deprived 
of its epidermis, it is of a light brown colour externally ; 
it has a slight odour, but the taste is bitter and roughly 
astringent. Its properties are readily extracted by water 



TANNING MATERIALS. 71 

and by proof spirit. Its constituents are tannin (about 
15 per cent.), gallic acid, uncrystallisable sugar, tannates 
of lime, magnesia, potash, &c. The inner part of the 
bark, as before observed, contains the largest proportion 
of tannin. 

Barking of Trees. — Since observation has proved that 
tannin exists in the bark of trees during spring time to 
a much greater extent than at any other period of the 
year, it must be evident that great care is necessary to 
obtain the bark when it is in a condition most favourable 
to the requirements of the tanner. Until the subject had 
been thoroughly investigated — and in this the careful 
researches of Davy and other scientific men have been of 
immense service to the tanner — the rind of old oaks was 
deemed of more value for tanning purposes than the pro- 
duct from younger wood. Experience, and a more in- 
timate knowledge of the chemistry of the subject, have 
shown that not only does the bark of younger wood yield 
more tannin than that from older trees, but the leather 
prepared with it is softer and whiter. " Doubtless the 
best age at which the trees should be barked is from 
eighteen to twenty-five or thirty years ; but owing to the 
importance of the timber for building and other purposes, 
rarely are trees of this age felled in England or European 
countries. In France, however, they harvest the bark of 
the oak at this age, but the wood is not turned to further 
use, excepting for the manufacture of charcoal, owing to 
this variety not being adapted for the builder. In France, 
too, the advantage may be gained of collecting the bark in 
the spring, at a time when the sap is in full flow, and 
when there is most tannin contained in it ; but in other 
countries, where the bark of the tree constitutes only an 
inferior secondary product, compared with the wood, this 
season is not chosen, in consequence of the timber being 
cut when the sap is in active circulation, and thus less 
liable to decay." — Muspratt. 

The period for debarking the trees in England, Holland 
and America, is about June, but this depends upon the 
mildness of the winter and spring. Barking is performed 



72 LEATHER MANUFACTURE. 

by cutting two circular bands round the trunk, about two 
or three feet apart; a longitudinal strip is then cut from 
one band to the other and the bark loosened at the upper 
band and stripped off by means of peeling irons, the bark 
being beaten when necessaiy. The strips, when removed, 
are spread out to dry, in beds, in a shady situation, and they 
are turned over occasionally to prevent the bark from 
heating. 

The harvesting of the bark requires to be conducted 
with great care, otherwise not only will the bark suffer 
loss of tannin, but also produce an inferior leather in the 
tan pits. Muspratt observes, " For the most part, or, 
indeed, in all cases, the bark should rest on hurdles 
elevated more or less from the ground, in an inclined 
state, and the fragments ought never to be heaped 
together more than twelve to eighteen inches in thickness. 
Provision ought to be made to protect the bark from the 
rain, and the whole should be turned at least once a week 
till quite dry. After this it is usually stacked in rect- 
angular heaps, and protected by thatch, if not by a roof, 
from rain and wet." 

In the year 1897 it was stated that about 40,000 tons 
of oak bark was annually imported into England from 
Germany, the Netherlands, and ports in the Mediterranean, 
but there is no means of ascertaining how much English 
oak bark is obtained. 

Davy gives the following quantities of tannin contained 
in oak bark : — 

480 lbs. of entire bark, of a middle sized oak, cut in 

spring 29 lbs. 

,, coppice oak 32 „ 

., oak cut in autumn 21 „ 

"White cortical layers 72 „ 

According to Braconnot, oak bark contains, besides tannic 
acid, tannates of the earths, gallic acid, pectin, and lignin. 

The proportions of tannin in Elm, Willow, and other 
barks, &c, are given in the foregoing table. 

Cork-tree bark is obtained from Quercus suber, a species 
of oak growing in Spain, Tuscany, and the islands of 



TANNING MATERIALS. 73 

Corsica and Sardinia, and on the northern coasts of 
Africa. The outer layer or bark of the tree constitutes 
what is known as cork, while the inner layer, which is of 
considerable thickness, is procured, from its richness in 
tannin (about 12 per cent.), as a tanning material, the 
greater portion of which is employed by the tanners of 
Ireland. 

Nut-galls. — These remarkable excrescences, which con- 
tain a large percentage of tannin, and also gallic acid, are 
imported largely into England from Smyrna, being the 
produce of Asia Minor ; also from Aleppo, the produce of 
the vicinity of Mosul in Kurdistan, a province of Persia. 
They are also imported from Bombay. Besides the names 
applied from the places whence they are obtained, the 
Levant galls are distinguished by their physical character- 
istics, being called Blue or White galls. The Blue galls 
vary in size, and are of a bluish-grey colour. They are 
gathered before the insect [Cynips] becomes fully de- 
veloped, or worked its way out of the nut. Some of these 
are larger, and are called Green galls, from being of a 
greenish colour. They exhibit on their otherwise smooth 
surface, a number of bluntly-pointed tubercles, which 
would appear to be the apices of leaves stimulated into 
unnatural growth. The best galls are heavy, hard, and 
shining, and break with a short flinty fracture. White 
galls are so called from being of a lighter colour than the 
others, but still of a greyish or yellowish hue. They are 
distinguished by being perforated with a small round 
hole, by which the insect had escaped. They are usually 
less heavy than the others, have a larger internal cavity, 
and are not so astringent. A third variety, called Large 
Mecca galls, are sometimes imported from Bussorah ; they 
are called Dead Sea Apples, and Mala insana. They are 
identical with some specimens brought by the Hon. B. 
Curzon from the Holy Land in 1847. They are spherical 
in shape, and surrounded about the centre by a circle of 
horned protuberances. They are astringent like other 
galls, and, when fresh, are said to be purple and shining. 
They are thought to be the produce of a peculiar variety 



74 LEATHER MANUFACTURE. 

of Quercus infectoria, which grows on the mountains near 
the Dead Sea. Peculiar galls of an irregular shape have 
occasionally been imported from China, where they are 
known by the name of Woo-pei-tzee. They are very 
astringent, and are supposed by Dr. Schenk to be formed 
by the puncture of the leaves of the Rhus semialata (Tere- 
binthacas) by a peculiar species of Aphis. 

Tanning Extracts. — Catechu. — This important tan- 
ning material is also known in commerce by the names 
Cashew, Cutch, Gambler, and Terra Japonica (Japan earth). 
Catechu is properly an extract prepared from the wood of 
Acacia Catechu, but the term is now applied to other 
extracts similar in appearance and properties. The leaves 
of the Uncaria gambir yield an extract which is known in 
commerce as Terra Japonica, Gambir, or Gambler, which 
is prepared in square pieces or blocks (cube gambier). 
The acacias, however, are most famous for the secretion 
of astringent matter in the wood, bark, and legumes (seed 
vessels) of various species, from which the catechus of 
commerce are obtained. Catechu is generally in square or 
roundish pieces or balls, varying in colour from a pale 
whitish or light reddish brown, to a dark brown colour ; it 
is either earthy in texture, lamellated, or presents a smooth 
shining fracture. Some kinds are more friable (easily 
crumbled) than others, and all are without smell. The 
taste is powerfully bitter and astringent, and leaves a sweet 
after-taste. The pieces are generally of a darker colour 
externally than they are inside. Some kinds are covered 
with rice husks, others are enveloped in leaves. The pale 
variety is usually distinguished from the dark coloured, 
and is said to be imported from Calcutta, but we have 
obtained both kinds in the bazaars there, the pale being 
imported from the upper provinces, and the dark from 
Pegu and Singapore. The dark brown catechus are ob- 
tained from Bombay, but both kinds may no doubt be 
prepared from the same tree, as a greater degree of heat, 
or longer continued heat, and greater exposure to light, is 
said to produce the dark colour. The dark are heavier, 
more dense in texture, and have a resinous fracture. The 



TANNING MATERIALS. 75 

largest portion of good catechu is taken up by water, 
especially when boiling, the infusion being of a light red 
or reddish-brown colour, according to strength : it reddens 
litmus, and is strongly astringent in taste. It yields a 
precipitate with the salts of ammonia, also with acetate of 
lead, and one of a blackish-green colour with the salts of 
the sesquioxide of iron. — Dr. Royle. 

Sir Humphry Davy, in analysing the dark and pale 
catechu, or those of Bombay and Bengal, obtained from- — 











Insoluble 




Of Tannin. 


Extractive. 


Mucilage. 


Residuum. 


Dark catechu 


.. 109 


68 


13 


10 = 200 


Pale „ 


.. 97 


.. 73 


16 


14 = 200 



The principle which Davy termed extractive has since 
been named CatecMne, or Catechaic acid. This is most 
easily obtained by treating gambier with cold water ; the 
tannin being dissolved, the insoluble residue is impure 
catechine, which may be purified by dissolving in alcohol 
and subsequent crystallisation, when it has the appearance 
of a white powder, but is in the form of silky needles, of a 
somewhat sweetish taste, producing a green colour with 
salts of iron. M. Soubeiran, who made a series of experi- 
ments with catechu, came to the conclusion that Pegu 
catechu is the most astringent of all the vegetable astrin- 
gents ; next to this, in astringency, is Jamaica kino ; next 
Amboyna kino ; fourth on the list is Indian catechu, and 
fifth, extract of rhatany. 8 parts of Pegu catechu are 
found to contain as much tannin as 10, 12, 14, and 15 
parts of the others respectively. 

The characteristics of the principal varieties of catechu 
are as follows : — 

Bombay Catechu.— Firm, brittle, dark brown, of a 
uniform texture, and a glossy, semi-resinous and uneven 
fracture. Specific gravity, 1*39. Richness in tannin, 52 
per cent. 

Bengal Catechu. — Rusty brown colour externally ; 
porous, and more friable than the preceding. Sp. gr. 1'28. 
Richness in tannin, 49 "5 per cent. 

Malabar Catechu. — Resembles the last in appearance, 



76 LEATHER MANUFACTURE. 

but is more brittle and gritty. Sp. gr. 1'40. Richness 
in tannin, 45*5. — A. J. Cooley. 

Kino, or Gum Kino. — This well-known astringent sub- 
stance is described in the British Pharmacopoeia as " the 
juice flowing from the incised bark of the Pterocarpus 
marsupium, or Indian kino-tree, hardened in the sun ; it 
is also the concrete juice of Pterocarpus erinaceus (in 
Africa), and of other undetermined genera and species/' 
From the uniformity of its appearance, it would appear to 
be the natural gummy exudation of some one plant, but 
several kinds of kino are met with in commerce which are 
known to be the products of various plants, as that of 
Butea frondosa, from India, Botany Bay kino, produced 
by Eucalyptus resinifera, or brown gum tree, also a 
Jamaica and a Columbian kino, and sometimes an extract 
of rhatany has been included in the list. The genuine 
kino has been supposed to come from the west coast of 
Africa, but it is understood that the best is now imported 
from Bombay. 

Kino is in small, irregular, somewhat angular, glistening 
fragments, of a dark brown or reddish-brown colour, 
brittle, and affording a powder which is lighter coloured 
than the masses. It is without odour, and has a bitterish, 
highly astringent, and ultimately sweetish taste. It is 
not softened by heat ; cold water dissolves it partially, 
boiling water more largely, and the saturated decoction 
becomes turbid on cooling, and deposits a reddish sedi- 
ment. Alcohol dissolves the greater portion. It consists 
chiefly of a peculiar modification of tannin and extrac- 
tive matter, and in some of the varieties, of a minute 
portion of resin. — Royle. According to Vauquelin, it 
contains no gallic acid, but tannin and peculiar extractive, 
75 ; red gum, 24 ; insoluble matter, 1. Its aqueous solu- 
tion is precipitated by gelatine (with which it produces 
a gum, in consequence of the presence of a little cate- 
chine), by salts of iron, &c. The alkalis favour its solu- 
bility in water, but essentially change its nature, and 
destroy its astringent property. Soubeiran states that kino 
contains more tannin than Indian catechu, but less than 



TANNING MATERIALS. 77 

Pegu catechu, and also that infusions of kino and Indian 
catechu alike produce a brown colour with solutions of 
perchloride of iron, with which Pegu catechu forms a 
green. 

Gambier, Gambir, or Terra Japonica (Japan earth) is 
an extract from the plant Uncaria gambir — a native of 
Malacca and the neighbouring islands, and was imported 
from Singapore in 1904 to the extent of about 160,280 
cvvts. It occurs in the market in the form of bales weigh- 
ing about 2 cwt. each, but a superior article, called cube 
gambier, comes to us in the form of small blocks. For a 
long period the English tanners failed to understand the 
proper mode of employing this agent, for when employed 
alone, besides imparting a dark red colour to the leather, 
it produced a soft and spongy article. It is now better 
understood, however, and is much employed, in moderate 
proportions, in the preliminary stages of tanning. 

Hemlock Extract. — The great success of hemlock 
tanning in the Northern States of America, has led to the 
importation into this country of large quantities of an ex- 
tract of this important tanning material, which is exten- 
sively used, in combination with other tanning agents. 

Chestnut Extract. — This is another comparatively 
recent tanning material, chiefly imported from France, 
being obtained from the wood and bark of the tree. 

Oakwood Extract is now also very largely used as a 
tanning agent, as also, 

Larch Extract, or Hungarian Larch Extract, which is 
favoured to some extent by English tanners of light 
leathers. 

Quebracho Extract, from the bark of Aspidospermum 
quebracho, is also now largely used in Britain, Germany, 
and America. 

Sumach, or Sumac. — This much esteemed tanning 
material — especially for light coloured leathers — is a 
powder of the leaves, peduncles, and young branches of 
Rhus coriaria and B. cotinus (wild olive), the product of 
the former being employed by the tanner, more espe- 
cially in the preparation of morocco and similar leathers, 



78 LEATHER MANUFACTURE. 

while that from the latter is used in dyeing. Rhus 
coriaria is a shrub growing wild in Portugal, Spain, 
Italy, Sicily and France, which countries produce con- 
siderable quantities of sumac, varying in quality, and 
distinguished from each other by the habits of the plant, 
the colour, and other properties. The shrub grows to 
the height of from four to eight feet, with a crooked 
stem, covered with a reddish-grey bark ; its leaves are 
green on the upper surface and of a whitish colour on the 
under surface during spring and summer, but they acquire 
a reddish hue in autumn. The plant flowers in July, the 
blossoms being of a greenish-red, and it yields clusters of 
small crimson berries. 

Sumac, as a tanning material, is chiefly preferred, 
especially on the Continent, for its not imparting colour- 
ing matter to the leather prepared with it. It is stated 
that one drawback in its employment is that it deprives 
the skin of much of its softness and pliability. In the 
manufacture of morocco and glazed leather it is largely 
used ; and when mixed with bark or other tanning material 
it yields very good results. 

Muspratt says : — " Of the species of sumac in the 
market, the Sicilian is accounted the best. There are two 
kinds, one of which, the Alcamo, is the most esteemed. 
It is a very fine light green powder, containing very little 
woody matter, having an agreeable odour, analogous to 
that of the violet, and a strong astringent taste ; it con- 
tains very little colouring matter, though it gives a yel- 
lowish-green solution when macerated with water. The 
second variety inclines to a reddish yellow, has a feeble 
odour, with a less astringent taste than the foregoing 
variety. On this account it is not much employed in 
tanning, though extensively used in dyeing. Sicilian 
sumac is generally packed in bales weighing about one 
and a half hundredweight. Spanish sumac is various in 
quality, being less carefully prepared, and consequently 
more or less mixed with woody matter. The best sort 
comes from Priego, and is grown in the neighbourhood of 
Malaga. It is, like the Sicilian, finely ground, and 



TANNING MATERIALS. 79 

affords a colour of equal or greater brightness j its odour 
reminds one of the tea plant. "With water it gives a dark 
and more reddish solution than the foregoing. It is 
usually packed in bales of one cwt. The other sorts, 
Molina and Valladolid sumac, are next in quality ; they 
are very similar. Portuguese, or Porto, sumac is almost 
similar to the Priego, but is generally dirtier, and con- 
tains more mineral salts. Italian sumac has a dark 
brown colour, is free from woody matter, but feels granular 
in the hand, and has an odour like that of the bark, which 
possesses similar qualities to the leaves. Prench sumac is 
similaf to the preceding. Three sorts are collected. The 
Fauvis is almost equal to the Sicilian when well purified, 
and comes from Brignolles, near Marseilles. If less care 
be taken in its manufacture it approaches more to the 
quality of Malaga sumac ; it frequently goes under both 
these names. A second sort, Donzeri, and a third, Piiclis, 
are commonly used in the tanneries. A fourth variety, 
called rodou or redoul, obtained from the Coriaria myrti- 
folia, cultivated in Languedoc, is of a greyish-green 
colour. 

The method of preparing sumac for the market con- 
sists in collecting the twigs of the shrub whilst in full 
foliage and drying them in the sun. The leaves are after- 
wards separated by threshing, and are then collected and 
ground under mill-stones ; the powder is then packed in 
bales for the market. Sometimes the peduncles and more 
tender shoots are ground with the leaves, but since these 
portions of the shrub contain a good deal of tanning prin- 
ciple they do not much detract from the quality of the 
material. 

Rhatany Hoot. — The rhatany plant [Krameria tri- 
andria) is a native of Peru, where it grows on the 
slopes of the sandy mountains, more particularly near 
Huanuco, where it was discovered by Ruiz, who found 
that the root was employed by ladies for rubbing the teeth 
and strengthening the gums. The root is woody and 
branched ; the pieces vary from an inch to the size of a 
quill. The cortical part is reddish-brown, fibrous, and 



go LEATHER MANUFACTURE. 

easily separated from the central reddish-yellow woody 
part. The root is without smell, but has an extremely 
astringent taste without being bitter. The cortical por- 
tion contains a much larger percentage of the active 
principle than the interior ; the smaller pieces from the 
greater proportion of the bark are the most rich in tannin. 
An extract is sometimes imported from South America. 

Rhatany root consists of one-third matters soluble in 
water; these consist of tannin, 42*6; gallic acid, - 3 ; 
gum, extractive and colouring matter, 56*6 ; and krameric 
acid, 0*5. Water and alcohol both dissolve its active pro- 
perties, forming a reddish solution. According to Gmelin 
and Peschier, rhatany root yields : 

Gmelin. Peschier. 

Tannin 38-3 42-6 

Gallic acid — - 3 

Sweet matter 6 - 7 — 

Nitrogenous matter 2-5 — 

Mucilage 8 - 3 — 

Lignin 43 3 — 

Krameric acid — 0*4 

Gum, extractive, and colouring matter — 5G - 7 

99-1 100-0 

Mangrove Extract. — Of late years much attention 
has been devoted to mangrove bark and its extract. 
The mangrove species is found growing in swamps in 
most tropical parts of the world, the tannin-yielding 
trees being known as Bhizophora mangle, and other allied 
species. The trees grow in the tidal districts of East 
India and Borneo freely, and of late years several extract- 
ing plants have been installed in the latter country, and 
the tannin extract exported in the form of a dry crystal- 
live product known under various fancy names. The 
percentage of tannin contained in the bark varies con- 
siderably, some going as high as 45, whilst others yield 
only 5 per cent. The catechol tannin is easily extracted, 
but is of a deep reddish tint, which, when used alone, 
makes an objectionable coloured leather. The extract 
contains from 60 to 70 per cent, of tannin, and much of 
the colour is eliminated in the course of manufacture. 



TANNING MATERIALS. 81 

It is one of the cheapest forms of tannin now on the 
market, and bids fair to become very popular. 

Myrobalans (also called My rabolams). — The myrobalan 
is the fruit of several species of TerminaUa, namely Termi- 
naUa chebula, T. bellerica, T. citrina, and Emblica officinalis ; 
these trees abound in Hindostan, Ceylon, Burmah, &c. 
The myrobalan varies in size from that of a small hazel 
nut to that of the nutmeg. The tannin occurs in the pulp 
which surrounds the kernel. When employed alone in 
tanning, myrobalans deposit a considerable quantity of 
bloom or ellagic acid ; they are, however, generally used 
in com mnation with other tanning materials, from their 
usefulness in modifying the objectionable colour which 
some of the latter impart to leather prepared with them. 
Owing to the extreme hardness of the nut, or stone, it 
requires to be ground by a mill specially constructed for 
the purpose. 

Valonia. — This name is given to the calyx, or cup, of 
a large acorn, the fruit of a species of oak, Quercus cegilops, 
which abounds in Asia Minor, Koumelia, and Greece. 
Some botanists have recognised other varieties of Valonia 
oak, as Quercus macrolcpis and Q. stenophylla, growing 
in the Greek peninsula. The largest supply of valonia, 
however, comes from Smyrna. It has been stated that 
Palestine abounds with the valonia oak, and the late Mr. 
Sparke Evans thought that it might be successfully 
grown in Australia, and thus become a source of wealth 
to that colony, which, possessing neither large rivers nor 
extensive forests, has more need to cultivate shrubs of 
commercial value. The suggestion is a good one, and 
deserves to be further promulgated. 

In an interesting paper in the Tanners' Journal respect- 
ing valonia, the writer gives some very useful informa- 
tion, from his own personal observation, from which we 
extract the following: "The fruit begins to ripen in July, 
and is ready for the cultivator in August. Some small 
portion of it never attains maturity, and either falls off 
the trees of itself, or is beaten off in the shape of camata 
or camatina. These two trade terms signify those cups 

Q 



82 LEATHER MANUFACTURE. 

that have not opened fully, and remain with the acorn 
stunted, and so embedded in them that it cannot be 

extracted The acorns which grow in the cups are 

gathered with them, but the knocking about which the fruit 
is subjected to before it is finally despatched to Smyrna, and 
the mere fact of drying, suffice to detach a great number 
in the meanwhile, and the produce thus reaches our 
market with only a small portion of them. The valonia 
is put into sacks, and is then forwarded by camels to the 

nearest railway station The valonia, having 

reached Smyrna, is emptied into dry, commodious, and 
well-aired stores specially built here for the article, and 
then undergoes the process of picking and cleaning. This 
is done principally by women, children, and infirm old 
men incapable of hard work. The smaller, or ' spine,' is 
separated from the cups, which are placed apart. The 
former is always mixed with a proportion of earth and 
stones collected with the fruit from the ground, and has 
to be freed from this extraneous substance. The cups are 
placed in large heaps before the cleaners, who rapidly 
lay aside all the damaged cups and all the acorns, and 
push the remainder behind them with their hands after 
thus cleaning it. At the same time the Trieste cups are 
quickly thrown into separate baskets, and the valonia 
thus leaves the workers' hands in three distinct qualities — 
Mezzana, English, and refuse. The first, however, which 
consists of the finest large cups, is not picked out of all 
parcels. In many cases it is allowed to remain in the 
English quality, which then takes the name of 'natural,' 
from the fact of its thus containing all the sound cups 
originally produced." From this it will be seen that 
valonia of the second quality only is exported for 
England. 

Divi divi is the pod of a leguminous shrub (Ccesalpinia 
coriaria), a native of South America and some other 
tropical countries ; it is also cultivated in Madras, Hin- 
dostan, Ceylon, and other parts of India. The tannin of 
the seed-pod exists in the tissue beneath the epidermis, 
the seeds themselves yielding no tannin. The tannin is 



TANNING MATERIALS. 81 

generally extracted by boiling the material in separate 
pits, while others crush the pods in a mill, and employ 
them as dust for the handlers. The employment of divi 
divi in the tannery, however, appears as yet to be but 
imperfectly understood. Containing, sometimes, nearly 
50 per cent, of tannic acid, it should be a valuable tanning 
agent ; but since it also possesses a considerable propor- 
tion of mucilaginous and oily matter, it is very susceptible 
of fermentation, especially, it is stated, in warm weather, 
or when the atmosphere is subjected to electrical disturb- 
ance. Tlje late Mr. Sparke Evans said : " This causes, at 
times, much annoyance and some loss, as one of our Bristol 
tanners found to his cost, when one day, passing through 
his drying shed, he came to a pile of divi-tanned butts, 
which had been laid down to temper, but through which 
he was able to thrust his walking stick as through a 
honeycomb. Divi-tanned leather feels firm in dry, but 
soft in damp weather. A fortune is open to any one 
who can employ this article in tanning and prevent 
the dark colour which accompanies its use." To check 
the fermentation to which divi divi is specially liable, 
acetic acid, and more recently carbolic acid and salicylic 
acid have been used ; a preparation called Antigalline 
has also been used with some degree of success. 

Mimosa Bark. — This material is obtained from various 
species of Acacia — an extensive family, of which the well- 
known Sensitive plant is a remarkable member. The spe- 
cies from which the mimosa of commerce is derived are : — 
Acacia molissima, A. decurrens, A. pyeantha, A. dealbata, 
and some others. The acacias abound in Australia and 
Tasmania, and large quantities of the bark are exported 
to this country — by far the greatest quantity, however, 
coming from the former colony. Mimosa is generally 
chopped or ground previous to exportation, and it has 
also been introduced in the form of an extract. The 
bark contains varying proportions of tannic acid, the 
mean being about 24 or 25 per cent. Being exceed- 
ingly hard, the bark requires to be very finely ground 
to extract all its tannin. It makes a red leather, and 



8 4 



LEATHER MANUFACTURE. 



is frequently used with valonia to correct the colour 
produced by the latter. 

List of Tanning Materials. 



Common Name. 


Botanical Name. 


Part of 
Plant used. 


Where from. 


Aleppo Pine . . 

Algarobiall . . 
Almardelboom 


Phylanthus emhliea . . 
Finns excelepensis .... 

Beabejum stellatum . . . 


Seed pod 
Bark .... 
Bark .... 
Seed pod 

Bark 

Bark .... 
Bark .... 
Bark .... 

Extract . . 

Bark 

Seed pod 
Bark .... 

Leaves . . 
Nut .... 
Bark .... 
Bark .... 
Bark .... 
Bark .... 
Bark .... 

Nut 

Extract . . 
Bark .... 
Extract .. 
Bark .... 

Bark .... 

Bark and 
Extract 

Bark 

Bark .... 

Bark .... 
Bark .... 
Bark .... 
Extract . . 
Bark .... 
Brk.ofroot 
Seed pod 
Bark .... 


Bengal. 

Spain. 

Gt. Britain and Spain. 

South America. 

Africa. 

Australia and Tasmania. 

Australia and Tasmania. 

British Guiana and 

West Indies. 
Bengal. 
Hindostan. 
South America. 
"West Indies. 

Eussia. 

East Indies. 

Russia. 

Australia and Tasmania. 

Australia and Tasmania. 

West Indies. 

Australia 

Africa. 

Bengal. 

South America. 

Bengal. 

Australia and Tasmania 

Australia and Tasmania. 

N. America and Spain. 

South America. 
British Guiana and 

West Indies. 
Spain, Italy. 
"West Indies. 
South America 
Bengal. 
"West Indies. 
Fiance. 

South America. 
South Africa. ' 


Arok kenema 






Balsamo .... 
Baramalli, or 

pump wood 
Bearberrj' .... 
Betel 

Black wattle . . 
Black wood . . 
Blood wood . . 


Carpon brevifolium . . 


Arctostaphilos uva ursi 


Acacia nwllissima .... 
Acacia melanoxylon . . 


Blue gum .... 
Butea-kino . . 


Eucalyptus globulus . . 
Pyenocamamacrophylla 


Celery Pine . . 
Cherry tree . . 
Chestnut .... 
Cevil 


Fhyllocladus aspleni- 

folia 
Exocarpus cupressi- 

formns 


Cork tree .... 
Crab wood .... 
Curmpuay .... 


Avicennia nitida 

Carapa guianensis .... 


Cutch 

Cuyama 




Dentelaria .... 
Divi divi .... 
Doomboom . . 


Plumbago eitropcea . . . 
Ccesalpinia cor i aria . . 



TANNING MATERIALS. 



85 



Common Name. 


Botanical Name. 


Part of 

Plant used. 


Where from. 


Galls 


Quercus infectoria . . . . 


Gall nuts 


Turkey. 


Gambier (Terr; 




Extract . . 


East Indies. 


Japonica) 








Gaub 


Diospyros glutinosa . . 


Root 


Hindostan. 


Hemlock 


Abies canadensis 


Bark .... 


North America. 


Hemlock 


Geranium maculatum 


Root anc 
Extract 


North America. 




Tlceocarpus dentatus . . 


Bark and 
Extract 


New Zealand. 


Hog plum 




Bark .... 


British Guiana and 
West Indies. 


Holm tree, or 




Bark .... 


Italy. 


Green Oak" 








Honeysuckle . . 


Banlcsia australis 


Bark .... 


Australia and Tasmania. 


Huldi 




Bark .... 

Extract . . 


East Indies. 

Australia and Tasmania. 


Iron bark .... 


Eucalyptus resinifera 


Kararalli .... 




Bark 


British Guiana and 
West Indies. 






Extract . . 
Bark .... 


France. 


Kermes Oak . . 


Quercus cocci/era . . . . 




Pterocarpus marsupium 


Extract . . 


Africa. 


Knoppern .... 


Quercus pubescens .... 


Galls .... 


Italy and Hungary. 


Krupelboom . . 


Leucospermum cone- 
carpum 


Bark .... 


Africa. 


Kullaballi 




Bark 

Bark .... 


Russia, N. America. 




Larix americana .... 






Bark 


Great Britain. 






Extract . . 
Root .... 


Borneo, East Indies. 
Russia. 


Marsh Rose- 




mary 










Acacia molissima .... 


Extract . . 


Queensland, Victoria, 








and Tasmania. 


Mocbrus .... 


Bombax inalebarica . . 


Extract . . 


Bengal. 


Molle 




Leaves . . 
Bark .... 


South America. 
British Guiana and 
West India. 


Mora 












Bark 


South America. 

Hindostan. 

Hindostan. 


Myrobalans . . 
Myrobalans . 




Terminalia cherbu 7 a . . 


Fruit . . . 


Myrtle 


Faqus Cunninghami . , 


Bark 


Australia and Tasmania., 


Myrtle 


Rhus myrtifolia .... 


Bark .... 


Italy. 


Neb neb 


Acacia nilotica 


Seed pod 


Africa, Nubia. 


Oak 


Quercus pedunculata . . 


Bark .... 


Great Britain. 


Oak 


Quercus sessiliflora . . . 


Bark .... 


Great Britain. 


Olive 




Bark .... 


Italy. 


Palacby 




Extract . . 


East Indies. 


Pomegranate 


Tunica qranatum .... 


Fruit shell 


Hindostan. 


Purimbaa .... 


Fusarmis compressus . . | 


Bark .... 


Africa. 



86 



LEATHER MANUFACTURE. 



Common Name 


Botanical Name. 


Part of 
Plant used. 


"Where from. 


Quebracho . . 


. Aspidospermum que- 
bracho 


Bark .... 


South America. 


Quercitron 


. Quercus tinctoria .... 


Bark .... 


North America. 


Red birch . . 


. Coriaria ruscifolia . . . 


Bark .... 


New Zealand. 


Red birch . . 


. Eugenia maire 


Bark .... 


New Zealand. 


Red birch , . 




Bark 


New Zealand. 


Rhatanv . . 


. Krameria triandria . . 


Root .... 


South America. 


Saffron .... 


. Crocoxylon excelsum . . 


Bark 


Africa. 


Sassafras . . 


. Atherospermamoschata 


Bark 


Australia and Tasmania. 


Saul tree . . 




Bark .... 


East Indies. 


Seaside grape 




Bark .... 


British Guiana and 
West Indies. 




. Casuarina quadrivalvis 


Bark 


Australia and Tasmania. 


Silver wattle 




Bark 


Australia and Tasmania. 


Sirnabelli . . 


. Nectandra 


Bark .... 


British Guiana and 
West Indies. 








Bark .... 
Bulb .... 


East Indies. 
Africa. 






Statice,orMrs 




Root .... 


Russia, North America 


rosemary 








Stone pine. . 




Bark .... 


Spain. 


Subaujuna. . 


. Moving a pterygosperma 


Bark .... 


Hindostan. 






Leaves and 
twigs 


France, Italy. 


Tamarisk gall 




Galls .... 


East Indies. 






Bark 

Bark .... 


New Zealand. 
North America. 


Tarsekeha . . 


. Phyllocladus tricho- 




manoides 






Tasman. laurf 


il Anopterus glandulosa 


Bark .... 


Australia and Tasmania. 






Seed pod 
Extract . . 


East Indies, 


Terra Japonic 




Bengal. 


Tormentil . . 


. Tormentilla potentilla 


Root .... 


Spain. 




. Weinmannia racemosa 


Bark 


New Zealand. 


Tuga veca . . 


. Stryphnodendron bar- 
batemas 


Bark 


South America. 




. Cassia auriculata .... 


Bark 


Hindostan. 






Acorn cup 


Turkey. 


"Wagen boon 


l . Protea grandiflora .... 


Bark 


Africa. 


Water plain 


- Polygonum amphibium 


Root .... 


North America. 


tain 








White man 


- Avicennica tormentosa 


Bark 


South America. 


Willow .... 




Bark .... 
Bark 


France. 
France. 





Miscellaneous Tanning Materials. — The shell of the 
seed of Sapindus emarginatus, an East Indian plant, is said 



TANNING MATERIALS. 87 

to contain 31 per cent, of tannin. Samples of the African 
gall nut of Tamaria are said to contain 56| per cent, of 
tannin. The bark of Tamaria gallica gave, on analysis, 
3 - 52 per cent, of tannin, and the bark of Terminalia Jbr- 
mentosa, of the same family as that from which myrobalans 
are obtained, is reputed to yield 26 per cent, of tannin. 
The bark of the common alder (Alnus glutinosa) is said to 
yield about 16 per cent, of tannin. The Eucalyptus leu- 
coxylon, or iron-bark of Victoria, yields about 22 per cent. 
of kinotannic acid ; Eugenia Smithii, or Australian 
myrtle-tree, is said to contain 17 per cent, of tannic acid, 
with frgm 3 to 4 per cent, of gallic acid. The shells of 
the pomegranate fruit yield about 13 per cent, of tannic 
acid. 



CHAPTER VIII. 

ESTIMATION OF TANNIN 

Examination of Bark. — Determination by Specific Gravity. — The Barko- 
meter. — Chemical Methods of Estimating Tannin. — Davy's Method. — 
Bell Stephens' Method. — Hammer's Method.— Lowenthal's Method. — 
Mr. Hewitt on Lowenthal's Method. — Mr. Procter on Lbwenthal's 
Method. — Ramspaoker's Method. The Tannometer. — Casali's Pro- 
cess. — Standard Method. — International Association of Leather 
Trades' Chemists. 

When we consider the vast number of tan-yielding vege- 
tables which have been brought to the tanner's notice since 
the days when Davy first investigated the subject, the 
variable characteristics of the different tannins, as shown by 
Gmelin, Stenhouse, Procter, and others, and the difference 
in the percentage of tannin in the various plants, or parts of 
plants, which enter the market for his use, it will at once 
become evident that the tanner should be in possession of 
some means by which he may estimate the true value of 
all tanning materials with which he may have to deal. 
Moreover, when it is borne in mind that the proper condi- 
tion of the tanning material may be seriously affected by 
damp or long exposure to the air, by which its active 
principle becomes converted into a product useless to the 
tanner, it is of the highest importance that the true per- 
centage of the active principle (tannin) should be deter- 
mined from a fair or average sample, before the bulk of 
the material — no matter from what source — is purchased 
and paid for. 

With a view to aid those who may desire to test the value of 
their tanning materials, we purpose giving — as free as pos- 
sible from unexplained technicalities — some of the methods 
adopted, commencing with those of the most simple cha- 



ESTIMATION OF TANNIN. 89 

racter. Before doing so, however, it may be well to con- 
sider what are the proper physical characteristics of the 
leading tanning material — oak-bark. 

Examination of Bark. — The bark is usually in long 
strips, of a coarse fibrous texture, and not easily reduced to 
powder. When deprived of its epidermis, it is of a light 
brown colour externally. The odour is faint, but the taste 
bitter and very astringent. — Royle. A good bark is 
known by its colour. The most highly esteemed is that 
which is white outside and reddish inside, rough and dry 
on the side of the wood, breaks easily, and gives less 
ligneous-( woody) matter ; the taste most astringent with a 
strong smell when ground. A sign of bad quality is 
when the epidermis and cortex (bark) are very thick 
and have a blackish colour ; in this case the bark is too 
old, and has experienced the commencement of decay. 
It is the same with bark which has been left a long 
time exposed to rain. The inner side, which should be 
reddish, has lost its colour, and the other parts, which 
have become darkened, have lost a part of their property. 
— Dussauce. 

Determination by Specific Gravity. — It is well known 
that in all arts in which solutions of chemical sub- 
stances of various degrees of strength are employed, the 
approximate strength of the solutions is determined 
by means of an instrument called a hydrometer. This 
instrument consists of a long glass tube with a small 
bulb partly filled with mercury or small shot at its lower 
end, and a somewhat larger bulb at a short distance above 
the mercury bulb. A graduated paper scale is enclosed 
in the longer stem of the tube, which is divided into tenths. 
When the hydrometer is floated in distilled xoater, it sinks 
to the top of the scale, which is marked 1,000 or (zero) — 
the specific gravity of water. This is taken as the standard by 
which the specific gravity of all other fluids is determined. 
Since alcohol and ether, however, are lighter than water, 
it is evident that such an instrument would not be of ser- 
vice in determining their strength or specific gravity; 
therefore, hydrometers for ascertaining the specific gravity 



9 o 



LEATHER MANUFACTURE. 



of liquids lighter than water are constr acted for the use of 
distillers, manufacturing chemists, and others. 

The Barkometer. — To enable the tanner to ascertain 
the tanning strength of his liquors, an instrument has 
been devised, called a barcometer or barkometer, and is due 
to the ingenuity of Mr. W. Pike, of New York. It is thus 
described by Morfit : — 

" It is made wholly of glass * (see Fig. 3), a d being 
the stem, enclosing a graduated paper scale ; B is a 
spherical bulb, and C a smaller bulb at 
its base, containing quicksilver or shot, 
which serves as ballast to retain the 
instrument in a vertical position in the 
liquid. The scale on the stem is equally 
divided into five or ten wide spaces, and 
each of these again subdivided into ten 
narrow spaces. The zero point of the 
scale is made by plunging the instru- 
ment into distilled water at 58° Fahr., 
and adding mercury to the bulb until 
it sinks to nearly the top of the stem 
at a. A solution of ten parts of bark in 
ninety parts of distilled water having 
been made, the hydrometer is then 
plunged into the liquor, and the point 
to which it sinks therein, say b, is 
carefully and accurately marked upon 
the scale and rated at ten as compared 
with the zero point. Each of the 
grand divisions consequently repre- 
sents ten per cent, of bark, and each of 
the smaller ones or subdivisions corre- 
sponds with one per cent, of the bark. It is very easy, 
therefore, after having determined the length of the stem 
from zero which sinks in a normal solution of bark, to ap- 
portion the rest of it with the aid of a pair of dividers, 
so that every interval thus apportioned shall be equal to 
that fixed by experiment. 

* Crass barkometers are now often used in the tanyard. — Ed. Fifth Edition 




Pis:. 3. 



ESTIMATION OF TANNIN. 



9' 



"When, therefore, this instrument sinks into a bark 
liquor to 20°, 30°, or any other degree, the number indi- 
cates the percentage of tanning 
power. [A convenient form of 
hydrometer glass is shown in 
Fig. 4.] It is necessary to ob- 
serve that this instrument is 
applicable only to freshly made 
liquors, for otherwise confusion 
and want of confidence might 
ensue upon finding that it 
sinks, sometimes to a corre- 
sponding degree, in spent liquor. 
This is owing to the fact that 
the alterations which tanning 
liquors undergo during use and 
exposure may not diminish their 
density, though they impair or 
destroy their tanning power." 
Indeed, the accumulation of 
gallic acid, vegetable extractive, 
and other constituents of bark 
in much-used liquors, would 
render the barkometer practi- 
cally useless as an indicator of 

the presence of tannic acid. It should therefore only be 
employed in testing the strength of fresh liquors, and even 
then the liquors should always be tested at the mean tem- 
perature of 60° Fahr., since the gravity of the liquors is 
greatly influenced by their temperature. 

Chemical Methods of Estimating Tannin. — The earlier 
methods of determining the percentage of tannin in vege- 
table substances were based upon the well-known affinity 
of this substance for gelatine ; but it was soon discovered 
that when solutions of tannin and gelatine were mixed 
together, the first precipitate of tanno- gelatine contained 
a larger percentage of tannin than the last, and conse- 
quently the gelatine test was open to objection where 
absolute accuracy was required. This method of forming 




92 LEATHER MANUFACTURE. 

an approximate estimate of the percentage of tannin, how- 
ever, is useful in cases where the higher chemical testa 
would not be so readily understood. 

Davy's Method. — One ounce of dry bark is reduced to 
a fine powder and digested in a pint of boiling water, with 
frequent stirring. After twenty-four hours' repose, the 
clear liquor is filtered through a cloth. Now dissolve one 
drachm of the best isinglass in one pint of warm water 
with stirring ; add the isinglass to the water gradually, 
to prevent it from agglutinising. Take equal quantities 
of these two liquors and mix them together ; a flaky pre- 
cipitate is at once formed. The mixture must now be 
filtered and the precipitate collected, dried, and weighed. 
The difference of weight indicates the proportion of 
tannin. The precipitate (tanno-gelatine) generally con- 
tains forty per cent, of tannin. 

In examining this method of estimating tannin, Mr. 
Bortwick found that much of the precipitated gelatine 
remained in the filtered liquor, and could not be separated 
by the filter, and also that the first portions of the preci- 
pitate contained 50 per cent, of tannin, while the latter 
portions contained very little. There is no doubt, how- 
ever, that Davy's estimate was based upon the fact that 
the precipitate was a compound of gelatiDe and tannin, and 
if the weight of the first was known, the difference in 
weight, after careful drying, must of necessity be the weight 
of tannin absorbed. 

Davy also suggested the following method : A piece of 
skin is dried and weighed ; it is then immersed in the 
liquor containing tannin for some hours, after which it is 
dried and weighed again. The increase in weight gives 
the quantity of tannic acid. 

Bell Stephens' Method. — This plan, originally sug- 
gested by Davy, is based upon the power of skin to absorb 
tannin. A piece of skin, dried over a hot- water bath, is 
carefully weighed. It is then soaked in water at about 
90° Fahr., until perfectly soft, and is next immersed in a 
weak solution of the tannin to be examined, which should 
be heated to about 90° Fahr. In about seven or eight 



ESTIMATION OF TANNIN. 93 

liours the skin will have absorbed all the tannin, when it 
is again dried and weighed. The increase in weight 
acquired by the skin indicates the quantity of tannin it 
has absorbed. One advantage of this process is that the 
appearance of the skin, after being thus partially tanned, 
shows what colour the tanning material would impart to 
leather prepared by its agency. 

Another method of estimating the strength of tannins, 
upon the above principle, is to take a given weight of 
dried shavings of unhaired skin, to immerse them in warm 
water until thoroughly softened, and then to place them 
in a weak and warm infusion of the tanning material to be 
examined. After a few hours' immersion the fragments 
of skin are withdrawn and carefully dried over a water- 
bath ; when perfectly dry they are again weighed, when 
the difference in weight will show the amount of tannin 
which has been absorbed. Of course it is absolutely neces- 
sary, in adopting these methods of ascertaining the per- 
centage of tannin, to leave the skin sufficiently long in 
the liquor to absorb all the tannin ; and in order that this 
should be determined with certainty, a few drops of a solu- 
tion of gelatine may be added to the liquor after the skin 
has been removed, when, if no turbidity is produced by 
the gelatine, it may be concluded that the skin has taken 
up all the tannin. Again, it is of paramount importance 
that the skin, or fragments of skin, should be absolutely 
dry at the time of weighing, otherwise all calculations 
will be misleading. 

Hammer's Method. — The specific gravity of the tannin 
solution to be tested is first ascertained by means of the 
hydrometer before referred to. This will show the density 
of the solution as compared with water (1000). The 
tannin is next removed from the solution by immersing 
skin in it until all the tannin has become absorbed. The 
hydrometer is now again placed in the liquor, when the 
decrease in its density or specific gravity will be pro- 
portionate to the quantity of tannin in the original 
solution. 

Besides the above methods of estimating tannin, which 



94 LEATHER MANUFACTURE. 

may be considered to give fairly approximate rather than 
actual results, there have been many processes of a more 
purely chemical character introduced from time to time, 
from which we will select the one which has found most 
general acceptance as a reliable method in the hands of 
persons accustomed to laboratory manipulation. We refer 
to the process of L6 wen thai, which has been the subject 
of much consideration, and also to some modifications by 
which it has been rendered somewhat more easy of ma- 
nipulation. 

Lbwenthal's Method.— This method of estimating the 
percentage of tannin is generally accepted as reliable, 
though of a . somewhat complicated character. It is based 
upon the oxidising power of permanganate of potash ; and 
this system of analysis by oxidation is termed titra- 
tion. The material to be examined being mixed with 
an oxidisable substance, as indigo, for example, is titrated 
with the oxidising agent, which in Lowenthal's pro- 
cess is permanganate of potash. The process is thus 
described : * — " The instruments required, besides a 
good balance and a few glass beakers and funnels, are 
merely a flask gauged at the neck to hold a litre,f a 
few pipettes and graduated glasses, and a Mohr's burette 
with a glass tap. The latter is simply an upright tube 
with a tap at the bottom, graduated down the side like a 
measuring- glass, and the most suitable size for the purpose 
is one delivering twenty-five cubic centimetres, and divided 
into two hundred and fifty parts. 

" The following solutions must be prepared : I. Four 
grammes of pure permanganate of potash in three litres 
of distilled water. II. Five grammes of pure 'precipitated 
indigo ' in one litre of water. III. Dilute sulphuric acid 
— one part acid to three parts water. IV. Twenty-five 
grammes of good transparent glue, well swollen in cold 
water, and then dissolved by gentle heat, the solution 
being made up to one litre with water and saturated with 
pure table- salt. Y. A saturated solution of pure salt con- 

* Tanners and Curriers' Journal, March, 1877. 
f See French Tables of "Weights and Measures. 



ESTIMATION OF TANNIN. 95 

taining twenty-five cubic centimetres of sulphuric, or fifty- 
cubic centimetres of hydrochloric acid per litre. 

" Although this seems rather a formidable list, it is not 
a costly one, and all the solutions may be kept for a long 
time in stoppered ' Winchester ' bottles. To make an 
analysis, 10 grammes of sumach or 20*25 grammes of bark 
are exhausted by boiling with water, and the solution, 
when cold, made up to one litre. Of this infusion, 10 cubic 
centimetres are mixed with, say three-quarters of a litre 
of water, 25 cubic centimetres of the indigo solution, and 
10 cubic centimetres of the dilute sulphuric acid are added, 
and theri*the permanganate solution is run in drop by drop 
from the burette, with constant stirring, till the deep blue 
of the indigo changes to a clear yellow, and the moment 
this takes place we note the quantity of permanganate 
used. We will call this A. Next we repeat exactly the 
same process with the indigo and sulphuric acid alone, 
and we will call this quantity B. Then subtracting B 
from A, we obtain the amount of permanganate consumed 
by the total astringent of 10 cubic centimetres of our 
tannin infusion. The permanganate acts, of course, as an 
oxidising agent, oxidising and consuming both the tannin 
and the indigo; but as the tannin is the most readily 
oxidised of the two, it is consumed first, and when the 
indigo is all bleached [decoloured], we may be sure that 
the tannin is destroyed also. In order, however, to obtain 
this satisfactorily, the proportion of indigo should be such 
as to require about twice the quantity of permanganate 
which should be consumed by the tannin alone. Thus, if 
the indigo alone requires 10 cubic centimetres of perman- 
ganate to decolourise it, the indigo and tannin infusion 
together must not take more than about 25 cubic centi- 
metres, and if it does so the tannin infusion must be 
diluted accordingly, or a less quantity employed. 

" The next step is to ascertain the proportion of gallic 
acid and impurities in the sample. To this end we mix 
100 cubic centimetres with 50 cubic centimetres of the 
salted gelatine solution, and then, after well stirring, add 
100 cubic centimetres of the salt and acid solution, and 



96 LEATHER MANUFACTURE. 

leave the mixture standing for some hours, or all night, 
and then filter it through filtering-paper. The filtrate 
should be perfectly clear. If we now test, say 50 cubic 
centimetres of this filtrate with permanganate and indigo, 
as before, we shall obtain the amount of permanganate 
required for the gallic acid and impurities alone, since the 
tannin has been entirely precipitated, and the gelatine has 
so trifling an action on the permanganate that it may be 
safely neglected. To make the working clearer we will 
take an example from Mr. Lowenthal's paper : — 

Ten grains of sumach were boiled in § litre of water, and after cooling, 
were made up to 1 litre. 

1-10 c.c. sumach infusion ) , „„ „ . 

25 c.c. indigo solution ) consumed 16-6 c.c. permanganate. 

The same repeated 16-5 ,, „ 

33-1 
Indigo alone 1 3 - 2 

Total permanganate for 20 c.c. ) __ „ 
sumach i 

2*50 c.c. nitrate from the \ 

gelatine | consumed 11*2 c.c. permanganate. 

25 c.c. indigo solution ) 

The same repeated 11-1 ,, „ 

92-3 

50 c.c. indigo alone 13-2 ,, 

Gallic acid and impurities 9 - l ,, 

" Now, deducting 9*1 cubic centimetres from 19 - 9 cubic 
centimetres, we have 10*8 cubic centimetres as the per- 
manganate equivalent to the tannin of 20 cubic centi- 
metres of sumach infusion, or - 2 gramme of dry sumach. 
If it be desired to compare two sumachs, these propor- 
tional numbers are all that is necessary, and indeed it 
will be quite safe to use them for comparing sumach 
with galls or pure tannin. In the same way bark may 
be compared with bark, and valonia with valonia, but 
it will not be safe to attempt by this means to com- 
pare bark with sumach or with valonia, because the dif- 



ESTIMATION OF TANNIN. 97 

ferent species of tannin consume different proportions of 
permanganate." 

Mr. Hewitt on Lbwenthal's Method. — With a view to 
testing- the accuracy of the results obtained by Lowenthal's 
method, Mr. F. W. Hewitt, of the Boyal College of Che- 
mistry, made a series of experiments with different tanning 
materials, and communicated the results of his labours to the 
journal referred to,* from which we make a few extracts. 
Mr. Hewitt observes : — " 1. The indigo-carmine solution 
employed must be quite free from suspended or undissolved 
matter. A convenient strength to use is such that 20 cubic 
centimefres thereof shall require about 12 cubic centimetres 
of permanganate solution (1*5 gramme of the salt to the 
litre). 750 cubic centimetres of water should be used to 
dilute this quantity of indigo, as the changes of colour 
from the blue to the various shades of green, and lastly 
yellow, are more distinct than if the solution be more con- 
centrated. A moderate amount of dilute sulphuric acid 
added to the indigo does not influence the reaction." Mr. 
Hewitt prefers, instead of using a beaker glass for the titra- 
tion of the permanganate solution, to employ a large flask, 
capable of holding about 48 ozs., and to agitate the con- 
tents by giving them a rotary motion during the reaction. 
He further observes, that if the permanganate solution 
"be run from the burette somewhat quickly, a slightly 
different reading can be obtained from that which is 
obtained when it is slowly introduced. When the approxi- 
mate amount of permanganate required is known, one cubic 
centimetre may be run in at a time, and the flask shaken, 
as before, about six times between each addition of per- 
manganate. In this manner more uniform readings are 
obtained." Mr. Hewitt says, that in precipitating the 
tannin by gelatine, Lowenthal's dilute acid solution "must 
not on any account be deviated from, as a more concen- 
trated acid (hydrochloric) would act upon the permanga- 
nate and liberate chlorine." 

Mr. Hewitt states that one objection to Lowenthal's 
method is that the gelatine solution requires a certain 
* Tanners' Journal, April, 1877. 

a 



98 LEATHER MANUFACTURE. 

amount of permanganate in the presence of free acid. 
This he observed by adding a little permanganate to an 
acidulated aqueous solution of gelatine, when the colour 
was discharged. " If the same tannin infusion be used in 
duplicate analyses with the same gelatine, I obtained very 
clear results, even when slightly different strengths of 
indigo were employed. Both indigo solutions, though of 
only slightly different degrees of concentration, should be 
previously titrated with permanganate solution." 

Mr. Hewitt gives the following result of his analyses, in 
conducting which he employed the same infusion of tannin 
and the same gelatine solution. The results are expressed 
in accordance with Lowenthal's proposition — namely, in 
percentage of oxidisable matter : — 

I. Sumach Infusion. 

l. 2. 

Tannin 45-3 45-8 

Oxidisable matter, not tannin 54-7 54-2 

II. Galls Infusion. 

Tannin 75-2 75-0 

Oxidisable matter, not tannin 24-8 25 - 

III. Oak-Bark Infusion. 

Tarnin . 87-3 87'3 

Oxidisable matter, not tannin 12-7 12-7 

In pursuing his experiments further, Mr. Hewitt found 
that the tanning material under examination should be 
boiled several times, with successive small portions of 
water, in order to obtain constant results in the deter- 
mination of the respective amounts of oxidisable matter 
present, and that a simple infusion in hot water did not 
afford such results. He also urges that the sample to be 
examined should be intimately mixed, so as to obtain a fair 
average in the portion to be examined. " In reference to 
the salted gelatine solutions," says Mr. Hewitt, " if the 
gelatine be not heated for a sufficient length of time on 



ESTIMATION OF TANNIN. 99 

the water-bath, with common salt solution, it assumes, on 
cooling, a jelly-like condition, and the solution from the 
precipitate which is formed when the gelatine solution is 
added to the tannin infusion, niters neither quickly nor 
clearly. This can, however, be entirely obviated by using 
a gelatin solution of a perfectly fluid consistency." He 
also says that he has not found any advantage in 
allowing the precipitate to stand for several hours, as 
recommended by Lo wen thai, to obtain a perfectly clear 
filtrate. He thinks that half an hour is sufficiently long, 
whereby the operation of testing tanning materials is con- 
siderably accelerated. The following results were ob- 
tained by Mr. Hewitt from the same sample of sumac, 
intimately mixed, and completely extracted. The strength 
of each of the four respective infusions being about h 
Grammes to the litre. 



Oxidisable matter, not tannin 


1. 

59-5 
40-5 


2. 
,59-2 
40-8 


3. 
59-64 
40-36 


4. 
59-68 
40-32 



100- 100- 100- 100- 

" It will, I hope, be allowed," observes Mr. Hewitt in 
conclusion, "by your practical readers, that a method 
which yields such results under the conditions which T 
have endeavoured to trace may well be called a useful 
method." 

The above results, based upon a careful and exhaustive 
series of experiments, clearly indicate the usefulness of 
Lowenthal's method of testing tanning materials, espe- 
cially when subject to the modifications which Mr. Hewitt 
has so ingeniously introduced. The difficulty which some- 
times arises, however, of separating minute particles of 
tanno- gelatine, which obstinately remain suspended in 
the filtrate, and thereby affect the accuracy of analyses in 
some degree, has frequently been a source of trouble in 
this and other cases in which gelatine has been employed 
to precipitate tannin. To overcome this, Prof. H. E. 
Procter hit upon the happy idea of mixing kaolin (china 
clay) with the liquid before filtration, the effect of which, 

LOFC. 



100 LEATHER MANUFACTURE. 

he says, " was instantaneous and complete. A perfectly 
clear filtrate was obtained without any of the tedious 
waiting which before was necessary, and it was not only 
free from tannin, so far as I have been able to ascertain, 
but also nearly so from gelatine, so that it only gives the 
faintest cloudiness with tannin solution." Kaolin is 
constantly used by photographers to remove the brown 
colour derived from the action of nitrate of silver upon 
albumenised paper, from their sensitising solutions, which 
it does effectually and instantaneously. A pinch or two 
of kaolin is put into a pint of discoloured sensitising 
solution, the bottle well shaken, and the solution at once 
filtered, when it passes through the filter perfectly bright 
and colourless. 

Prof. Procter on Lowenthal's Method.— Prof. Procter* 
thus describes the system he adopts in working Lowen- 
thal's method: — "I employ permanganate of the strength 
of 1 gramme per litre, and solution of the purest indigo- 
carmine of 5 grammes, with 50 cubic centimetres of 
concentrated sulphuric acid per litre, using a 25-cubic 
centimetre burette, and 20 cubic centimetres of indigo 
solution, which consumes about 15 cubic centimetres of 
permanganate. The quantity of astringent used must not 
require more than the remaining contents of the burette. 
The titration is performed in a white basin, as recom- 
mended by Kathreiner, with about three-quarters of a litre 
of good water, which it is best to measure approximately, so 
that if it contains any impurity which affects the per- 
manganate it should be constant, and thus eliminated with 
the indigo. The titration is finished when the pure yellow 
liquid shows a faint pinkish rim. This acid reaction, 
which is of extraordinary delicacy, is due to Kathreiner, 
and is quite different to the pink caused by excess of 
permanganate, being an effect common to all pure yellow 
liquids. I do not find it needful to make the titration so 
slowly as has been advised; the permanganate may be 
dropped rapidly, with vigorous stirring, so long as there 
is large excess of indigo, but as soon as the bottom of 
* Journal of the Society of Chemical Industry. 



ESTIMATION OF TANNIN. 101 

the basin can be seen through the solution it must be 
added very cautiously and with occasional pauses, to 
allow time for its complete mixture through so large a 
mass of fluid. 

"I make my infusion of such a strength that I can 
employ 5 cubic centimetres of the original liquid for each 
titration. This is repeated twice, and the results added 
together and denoted a. I then take 50 cubic centimetres 
of the infusion, and add 28 - 6 cubic centimetres of a freshly 
made solution of Nelson's gelatine of 2 grammes to 100 
cubic centimetres. After shaking, the mixture is satu- 
rated with salt, which brings the volume up to 90 cubic 
centimetres, and 10 cubic centimetres of dilute sulphuric 
acid (containing one volume of concentrated acid in ten) 
and a teaspoonful of pure kaolin are added. It is best to 
do this in a flask in which it can be well shaken, after 
which filtration may be at once proceeded with. Ten cubic 
centimetres of this filtrate ( = 5 cubic centimetres of the 
original infusion) are employed for a second pair of titra- 
tions, which are added as before, and the result denoted b. 
If, further, c be the quantity of permanganate required to 
oxidise 10 cubic centimetres of decinormal oxalic acid, and 
10 grammes of substance have been employed to one litre 
of infusion, c : [a — b) : : 6*3 : x, where x is the percent- 
age of tannin expressed in terms of crystallised oxalic acid. 
For the present I invariably calculate my results in this 
way, since we do not actually know the relation of any 
single tannin to permanganate, even Neubauer's number 
for gallo-tannic acid being probably too high, and Oser's 
for quercitannic acid being only a fair approximation. It 
happens, moreover, that this last equivalent (62 - 36) does 
not differ from that of oxalic acid (63) more than the ordi- 
nary limits of error of such estimation, and the substitution 
is therefore of no commercial importance, while it is 
surely better to employ a standard which is easily and 
exactly verified than one which is certain to be modified 
by further research, and so to run the risk of either having 
our results made useless for further comparisons or of 
establishing a false and arbitrary equivalent. What is 



ios LEATHER MANUFACTURE. 

wanted for practical purposes is not the absolute weight 
of tannin in the various materials, but only a means for 
the relative comparison of two samples of the same mate- 
rials, cross comparisons of different tannins being simply 
delusive." 

Hamspacker's Method. The Tannometer. — The fol- 
lowing is Dr. John Watts' s description of Muntz and 
Ilamspacker's apparatus, called a tannometer, for esti- 
mating tannic acid, by which the actual tanning power of 
any tanning material may be determined — " The appa- 
ratus may be briefly described as a shallow gun metal 
drum of about 200 cubic centimetres capacity, per- 
manently closed at one end by an india-rubber plate, and 
capable of being closed watertight at the other end by a 
piece of depilated hide, when clamped upon a stand over 
which the skin has been previously stretched. 

"The drum is perforated at the side with a screw, to 
admit the introduction of the tanning liquor, and is fitted 
above with a screw-piston to compress the india-rubber 
disc. When the piston is lowered the liquor is forced 
through the skin, while the latter retains the whole of the 
tannic acid. The density of the liquor is taken before and 
after the operation by means of a very fine hydrometer 
graduated to a special scale, when the difference expresses 
at once the percentage value of the liquor operated upon. 
In order to compare the results of this tannometer with 
Hammer's table of percentages of tannin in solutions of 
different densities, and to compare both with the results 
by evaporation, a number of experiments were undertaken 
by the inventor. The percentages only indicate the value 
of the particular sample under examination. The numbers 
in the first column were obtained hj taking the specific 
gravity at 15° C. (59° Fahr.) before and after removing the 
tannin and obtaining the percentage equivalent from Ham- 
mer's table. The third column was found by evaporating 
25 cubic centimetres in a platinum dish before and after 
the removal of the tannin, and drying the residue for three 
or four hours at 100° G. (212° Fahr.). 



By 


By 


Tannometer. 


Evaporation 


. . . . 40-44 . 


.. 47-43 


. . . . 30-50 


.. 49-02 


44-60 . 


. . 52-16 


25-32 . 


.. 26-30 


. ... 30-28 . 


.. 31-08 


30-16 . 


.. 31-72 


. ... 59-10 . 


— 


. ... 52-41 


. 57-90 


18-00 . 


. . 19-55 


... 33-94 . 


.. 35-20 



ESTIMATION OP TANNIN. 103 

By Specific 
Gravity, 

Cube Gambier 41-45 

Bale „ 42-24 

Cutch 47-70 

Valonia 25-32 

Myrobalans 32-30 

Mimosa bark 31-44 

Blue galls 6060 

Green,, 53-40 

Sumac 17-10 

Divi divi 34-50 

Casali's Process.— This is founded on the fact that a 
neutral*solution of sulphate of nickel, containing a salt of 
ammonium, completely precipitates tannin from its solu- 
tions, forming flocks which easily collect together. He 
prepares his standard solution as follows : — 2 - 89 grammes 
of pure sulphate of nickel, previously dried at 518° to 572° 
Fahr., are dissolved in boiling water with the addition of 
a few drops of sulphuric acid, and 100 cubic centimetres 
of a 30 per cent, solution of sulphate of ammonia are 
added. One-half the mixture is mixed, drop by drop, 
with ammonia, until it assumes a violet-blue colour. The 
other half is then added, and the whole diluted to one 
litre. The solution is not affected by glucose, glycerine, 
tartar, or alkaline oxalates and succinates. One cc. pre- 
cipitates 0'01 gramme of the tannin of galls, or 0*01497 
gramme of the tannin of oak bark. To determine the 
tannin, the sample of ware — 20 grammes, if it be supposed 
to contain 6 — 10 per cent., and 10 grammes or less if it 
contains more — is powdered and extracted with water at 
168° to 176° Fahr., so that the total bulk of the filtered 
solution may make up yo^ litre. Ten cc. of it are mixed 
with five cc. of alcohol, and the standard solution is 
allowed to flow into it, drop by drop, from a burette. As 
an indicator, he uses slips of filter paper steeped in a mixed 
solution of perchloride of iron and copperas. From time 
to time a drop is placed on a little square filter-paper, and 
allowed to pass through this upon the iron paper. The 
reaction is complete when a drop no longer blackens 
this paper. 



104 LEATHER MANUFACTURE. 

Standard Method. International Association of 
Leather Trades' Chemists. — There are few substances 
which present so many difficulties in the way of their 
accurate estimation as tannin. Although the subject of 
the accurate determination of the amount of tannin in 
any given substance has received the attention of chemists 
for a great number of years, it must be confessed that no 
absolutely reliable method has yet been discovered. 

One of the chief difficulties in dealing with tannin is 
its high molecular constitution, which permits of its being 
decomposed very readily, forming fresh compounds which 
introduce further complications into the proper estima- 
tion of the original tannin. One of the earliest methods 
of estimating tannin was to precipitate the tannin with 
a standard solution of gelatine ; but this and other 
methods involving the use of gelatine were found to be 
only approximate in their results, and not sufficiently 
reliable for employment in commercial analyses. It 
would occupy too great a space even to mention the 
many different processes, gravimetric and volumetric, 
which have been tried, without success, to solve this 
problem. Some methods which are satisfactory with one 
particular tannin material utterly fail when dealing with 
another of a different class. It is obvious that some 
means of estimating tannin had to be employed, and, in 
consequence, chemists adopted methods of tannin analyses 
which their own fancy dictated, the result being that 
great discrepancies in the percentage of tannin in the 
same sample occurred when analysed by two different 
chemists. 

As the subject of tannin analyses grew in importance, 
it became imperative that a standard method should be 
devised to be employed in all tannin estimations, which 
would at least procure concordant results, if not accurate 
determinations of tannin. With a view to establishing 
such a method, a conference of those principally interested 
was called in London in 1897, the result of which con- 
ference was the formation of an International Association 
of Leather Trades' Chemists, who agreed to adopt one 



ESTIMATION OF TANNIN. 105 

"standard" method in all tannin estimations. The 
method which was agreed upon is known as the " hide- 
powder filter method ;" but at the annual meeting of the 
association, additions to and alterations in the originally 
adopted method are constantly being made. The hide- 
powder filter method consists in detanizing the tannin 
solution by means of hide powder placed in a "bell 
form" of filter through which it is syphoned. The 
method is carried out as follows : First, the infusion 
of the tannin material, or the solution of extract (the 
strength of these depends on the material under ex- 
aminatidh, an infusion is usually made with between 20 
to 40 grms. of the material, according to its richness in 
tannin. An extract solution is made between 12 to 20 grms. 
of extract. In both cases 1 litre of the liquor is made), 
is filtered through what is known as the "candle" filter, 
which is used largely in bacteriological laboratories. The 
vacuum pump is used to facilitate this filtration, the object 
of which is to get rid of all insoluble matter. 

It is usual to filter only about half of the litre, the 
whole having been previously well shaken. 50 c.c. of 
the clear filtrate is taken for the estimation of the " total 
soluble" matter. This is done by evaporating to dryness 
in a weighed porcelain basin on a water-bath, and the 
residue is afterwards dried in an air oven at about 105° C, 
then cooled in a desiccator and weighed. A vacuum oven 
is preferable for drying the residue, as it lessens the ten- 
dency of the tannin matters to oxidise, thereby gaining 
in weight. 

The "total soluble" residue contains both tannin and 
non-tannin matters, so that it becomes necessary to 
separate them in order to estimate either the " tannin " 
or the " non-tannin." This separation is carried out on 
a fresh portion of the solution. The standard method 
consists in absorbing the tannin matters present in the 
liquor by means of the hide-powder filter already referred 
to ; and regarding the filtrate (which has become de- 
colourised in passing through the hide powder) as contain- 
ing non-tannin matters, a measured quantity is taken, 



106 LEATHER MANUFACTURE. 

usually 50 c.c. The first 30 c.c. from the filter is rejected 
as containing soluble matter from the hide powder, and 
the second 50 c.c. is evaporated to dryness in a weighed 
porcelain basin, and treated exactly as in the case of the esti- 
mation of the total soluble matters. The difference in the 
weight between the total soluble residue and the non- 
tannin residue represents the amount of tannin in 50 c.c. of 
the original tannin solution, and by a simple calculation 
the percentage of tannin matter in the original extract or 
tannin material can easily be determined. The water 
contained in a tannin extract is determined by drying 
a weighed quantity of the extract at 110° C, and weigh- 
ing and drying alternately until the weight is found to 
be constant. The residue from the moisture determina- 
tion is termed the "total dry matter." The difference 
in the weights between the total dry matter and the 
total soluble matter represents what is termed " insoluble 
at 15° C." 

It will be observed from the foregoing that the standard 
method of tannin estimation possesses only moderate 
claims to scientific accuracy, and differences in manipula- 
tion affect the final results. For instance, the particular 
manner in which the hide powder is packed in the bell 
filter has an important bearing on the results. 

There are many modifications of the hide-powder filter 
method, such as the American " shake " method, which 
consists in treating a definite volume of the clear tannin 
solution with a weighed quantity of hide powder in a 
glass tumbler, and the mixture is well shaken at frequent 
intervals in a machine constructed for the purpose. The 
mixture is afterwards filtered through an ordinary funnel 
having a plug of cotton wool in the neck, when the fil- 
trate is found to be completely detanised. In other 
respects the process is the same as that already described. 

The most unsatisfactory feature in all the methods 
where hide powder is employed is the difficulty of obtain- 
ing a regular supply of hide powder of the same quality. 
Experiments are being made with chrome hide powder 
prepared from chrome tanned hides, and the results are 



ESTIMATION OP TANNIN. 107 

said to be more uniform than those obtained with the 
ordinary hide powder. 

In conclusion, it is to be feared that the chemistry of 
the tannins is not yet fully understood, and when more 
light is thrown upon their chemical constitution, doubtless 
more scientific methods of analyses will be devised. 



CHAPTER IX. 
PREL1MINAR Y OPERA TIONS. 

Treatment of Green or Fresh Hides. — Method of Salting Hides. — Cleans- 
ing the Eaw Hides. — Dried Hides. — Softening Dried Hides. — Brain's 
Process. — Dry Salted Hides. — "Wet Salted Hides.— Schultz's Views 
on the Treatment of Hides. 

Preliminary Operations. — Since the condition of the raw 
hides, as they are received by the tanner, influences their 
preparatory manipulation, it will be necessary to consider 
them under the three different heads which indicate their 
condition, namely : 1. Green, or Fresh Hides ; 2. Dried 
Hides ; 3. Dry Salted Hides ; 4. Wet Salted Hides. The 
first embraces those hides which are furnished by the 
slaughter-houses and butchers, and the latter such as are 
imported from different parts of the world. 

Treatment of Green, or Fresh Hides. — Those hides 
which have been recently taken from the slaughtered 
animal require but little labour to cleanse from the ordi- 
nary " muck " which commonly adheres to them ; since 
the hides are sold by weight, however, it has sometimes 
been the practice of unfair vendors to augment their 
weight by purposely saturating them with such filthy 
matter. 

It occasionally happens that the green hides of the 
slaughter-house cannot be at once used by the tanner, in 
which case, especially in warm weather, the hides are 
salted, so as to check putrefaction. For example, if the 
hides are required to remain in stock for a week before 
undergoing the preliminary process of washing and liming, 
about four or five pounds of coarse salt are spread over 



PRELIMINARY OPERATIONS. 109 

eacli hide ; but if they have to be kept for a longer period 
about twice that quantity of salt is used. Imported 
hides, as those from South America, are treated with 
a still greater quantity of salt, sometimes as much as 
20 lbs. being used for each hide, according to the size 
and the season, the average quantity being about 15 lbs. 
per hide. 

Method of Salting Hides. — The Continental system of 
salting hides, known as Delande's method, consists in 
spreading the hides open upon the ground and sprinkling 
the flesh side with salt, but more liberally at the edges and 
along tKe spinal parts. The hides are then folded or 
doubled lengthwise down the centre ; the remaining folds 
are made over each other, commencing with the shanks ; 
next the peak of the belly upon the back ; afterwards the 
head upon the tail part, and the tail part upon the head, 
and lastly doubling the whole with a final fold, and forming 
a square [or cushion] of about two feet. This being done, 
they are piled three or four together, and left until the 
salt has dissolved and penetrated their tissue, which is 
generally in about three or four days. Thus prepared 
they are sent to market. Skins may be dried, even after 
having been salted, by stretching them upon poles with 
the flesh side outwards, and exposing them to dry air in a 
shady place. Ten pounds of salt in summer, and some- 
what less in winter, are requisite for each skin of ordinary 
size. — Dassauce. 

Cleansing the Raw Hides. — It is of considerable im- 
portance that the hides, before being submitted to the 
several operations which constitute the tanning process, 
should be freed from all adhering foul matter, blood, &c. ; 
in short, the hide should be clean. This is effected after 
the horns are removed by first steeping them in water for 
several hours — from one to twelve hours, according to 
their condition — and afterwards removing all the filth thus 
softened or loosened by washing in clean water, a run- 
ning stream, where practical, being preferable. When 
the hides are more than ordinarily dirty they must be 
removed from the soaking bath and scraped with a blunt 



no LEATHER MANUFACTURE. 

tool, Fig. 5, on the beam, trampled upon in water, and 
finally well rinsed. When a running stream is available 
it is considered a good plan to secure 
the hides to a rack, and this being 
fixed in the full force of the stream, 
Fig- 5 - the friction of the water loosens and 

dislodges the objectionable matter, whereby there is a 
considerable saving of labour. 

Dried Hides. — It will be readily understood that skins 
which have been deprived of their natural moisture by ex- 
posure to the air or the heat of the sun, without under- 
going any further treatment, for export purposes, merely 
require to have the moisture they had lost in drying 
restored to them to bring them to the condition of green 
or fresh hides. And this is so in fact ; but in order to 
facilitate the absorption of moisture by the indurated or 
hardened surfaces of the hides without wasting their sub- 
stance, a certain amount of mechanical treatment is neces- 
sary. If the skins could be soaked in boiling water they 
would very soon recover their normal condition ; but as 
gelatine is soluble in hot water, the skins, by such treat- 
ment, would not only lose considerably in weight, but their 
porous structure — so important to the free absorption of 
tannin — would become altered, if not destroyed. Dried 
skins, therefore, must be brought to a pliant state by cold 
soaking in the first instance, and by subsequent beating, 
rubbing, and soaking to render them supple. 

Softening Dried Hides. — The dried" or " flint " hides 
of Buenos Ayres, River Plate, and other localities, are first 
thrown into cold water, in which they are soaked from ten 
to fourteen days, according to their thickness ; but after 
being in soak for several days they are subjected to mecha- 
nical treatment by being forcibly rubbed or " broken " with 
the blunt tool on the beam, after which they are again 
soaked and then subjected to a process of beating, which in 
most establishments is effected by a machine called ihe 
fulling stocks, which, by repeated blows of the hammer or 
toes upon the partially softened skin, alternated by further 
soakings, eventually reduces the hides to nearly the con- 



PRELIMINARY OPERATIONS. 



in 



dition of fresh hides. An illustration of such a machine, 
as made by Huxham and Browns, is shown in Fig. 6. 




Fig. 6. 



Brain's Process. — A process for softening 1 dry hides 
and puring skins from lime has been introduced bj* - Mr. T. 
Brain, which appears to have commanded some attention 
from the trade. In an address to the Scottish tanners, he 
said, " I have succeeded in making a compound not only 
inoffensive, but emitting a pleasant odour, which I shall 
be prepared to sell under a registered title, and which for 
dressing leather is applicable with a little alteration in 
the use, and washing through clean cold water afterwards, 

with careful scudding Tanning of dressed leather 

prepared by my process does not require the liquor to be 
so strong or new at commencement as skins require by 
the bating or reducing system generally in use. By the 
old way the pelts have parted with so much gelatine that 
if they are put into very weak liquor they go on losing 
gelatine. But by using a moderately strong liquor for 
a day or two it closes the extremities of the fibrine, con- 
sequently the gelatine ceases to flow out, and they are put 



U2 LEATHER MANUFACTURE. 

into a weak liquor to ' recover breath.' By puring the 
pelt from lime and not reducing by bate, it retains all the 
gelatine, and should be well handled in a weak stale liquor 
for a day, and then shifted to increased strength daily, so 
that a gain of about 1 per cent, is kept up additionally, 
commencing at about 6 degrees for dressing and 10 de- 
grees for sole." 

Dry Salted Hides, as those from Texas, Pernambuco, 
&c, are treated much in the same way as dry hides, but 
are somewhat more readily softened than what are called 
" flint " hides. 

Wet Salted Hides are soaked in water to remove the 
saline matter, after which they are rubbed on the beam 
and again soaked, until they are in the proper condition 
for the lime-pits. 

Schultz's Views on the Treatment of Hides.* — " In 
all the processes, commencing with the soaking and mill- 
ing or wheeling, through the lime or bate, each pelt must 
be individually treated ; and if the conditions are much 
varied, more judgment and care will be necessary in their 
treatment as a whole than if they are substantially alike. 
In the latter case ordinary intelligence would suffice to 
perform creditable work. This degree of intelligence is all 
that the employer has a right to expect, and hence the 
importance of making as light drafts upon the brain power 
of his men as possible, by making the labour uniform on 
each piece of stock. How few calf- skin tanners in this 
country [America] think it important to classify their 
skins ! Do they not work all skins, from six pounds to 
twelve, in the same pack ? Whatever is classed as 'veal' go 
together ; the first selection that is thought of is when the 
finishers are wanting stock. The packs are then assorted, 
and the tanned skins are selected out and sent to the cur- 
rying shop, while the heavy ones are given another liquor. 
This is beginning at the wrong end : the selection should 
have taken place before the skins entered the beam house, 
when the advantages of classification would have been 
secured all the way through the process. 

* " Leather Manufacture." By Jackson S. Schultz. 



PRELIMINARY OPERATIONS. "3 

" In a well-regulated calf or kip-skin yard, from the 
time the skins enter the tannery they are mated (for 
reasons hereafter stated), and continue this connection 
through the whole after tanning process. But how can 
dissimilar sizes and substances be suitably paired, and so 
placed, grain to graiD, as to fully cover each other ? What 
has been said thus far goes to the advantage of the intrinsic 
quality of the stock ; but suppose some hides or skins are 
damaged, or partially so ? These should by no means be 
allowed to contaminate the good. They are the sick mem- 
bers, and must be placed in hospital under observation. 
They may not all have the same disease, and must be 
placed in different ' wards ' or apartments for special 
treatment. When one thinks of the indiscriminate and 
forcing processes which valuable stock receives at the 
hands of many tanners, the inhumanity of the treat- 
ment is forced on one's mind. Sick or well, strong or 
weak, large or small, the same methods, the same trying 
ordeal, must be passed by all, and that so few should break 
and fail is a wonder. 

"It remains only for me to say a word about the im- 
policy of working a variety of hides in the same yard. It 
is not to be denied that some tanners succeed in making 
good stock out of a variety of hides under treatment at the 
same time ; but this is the exception, and should not be 
ventured upon by the average tanner. At least one sea- 
son's or one year's hides should be of one kind, or as 
nearly so as possible. Buenos Ayres, Monte Yideo, and 
Rio Grande are sufficiently alike to be classed together. 
Central America and Matamoras, and even dry Texas, are 
possibly similarly conditioned. California and Western 
may be well treated as similar hides, requiring light treat- 
ment ; but there cannot be safely treated dry salted and 
dry flint hides in the same beam house ; lime and sweat 
stock cannot go through together without danger, or cer- 
tainly with the hope of the most satisfactory results. The 
best leather is made by tanners who work a uniform de- 
scription of hide. This is the usual experience, and is 
based on common sense." 



H4 LEATHER MANUFACTURE. 

These observations, emanating as they do from one of 
the most experienced and observant of American tanners, 
deserve the fullest consideration, and few, we should 
imagine, will question their wisdom. Of all the members 
of the trade in any country, Jackson Schultz will ever be 
held in esteem for his generous desire to promote the wel- 
fare of his trade by freely and ungrudgingly making 
known the results of his own vast personal experience for 
the benefit even of his competitors — an attribute but sel- 
dom, and it must be acknowledged with regret, found in 
those who follow the art of tanning in this country. 
Indeed, the reticence, " closeness," or so-called " conserva- 
tism " of the tanning trade in this country are, we think, 
to be deplored ; for were the followers of this great art to 
assist each other by the interchange of ideas, and by making- 
known such modifications of processes as may from time 
to time have proved successful, not only individuals, but 
the whole fraternity, as well as the general public, would 
be the gainers. 



CHAPTER X. 

D EPILATION, OR TINE AIRING SKINS AND HIDES. 

Depilation by Lime. — Properties of Lime. — Storing the Lime. — Liming. — 
Single Pit Method. — Working in Bounds.— Continental Method of 
Liming. — Supposed Disadvantages of the Lime Process. — Dr. Davy 
on the Action of Lime on Animal Matter. — Working on the Beam. — 
Rounding the Pelts. — Depilation by Sweating. — Cold Sweating. — De- 
pilation by Acids. — Depilation by Saccharine Matter. — Depilation by 
Caustic Soda. — Depilation by Bisulphide of Calcium. — Depilation by 
Charcoal. — Depilation by Sulphide of Sodium. — Palmer's Process. — 
Beck's Process. — The Pullman-Payne Process. 

Depilation by Lime. — The removal of the hair from 
skins and hides, called depilation, or unlmiHng, and which 
may also be termed dehairing, is performed by several 
different processes, bnt that which rinds most favour in 
this country is that known as the lime process. When a 
fresh skin is allowed to remain for a certain length of time 
in a mixture of caustic (that is fresh) lime and water, the 
cuticle or epidermis, together with its hair, readily sepa- 
rates from the cutis or true skin, while at the same time 
the fatty and fleshy matters of the under portion of the 
skin become easily separable by the operations of the 
fleshing knife. During the soaking in the lime-pits, the 
fatty matters become partially converted into an in- 
soluble lime soap, whereby the fleshy portions are loosened 
and may be readily scraped from the under surface of the 
true skin. 

Depilation by lime is the oldest method known, and 
although it possesses certain disadvantages, it is still more 
extensively adopted than any other method of unhairing. 
The lime is made into what is called milk of lime, by 



u6 LEATHER MANUFACTURE. 

mixing recently slaked lime with water in varied prc-por- 
tions, the weakest mixture being that in which the hides 
are first soaked, and in which they are allowed to remain 
for one or two days, after which they are transferred 
to another pit containing a stronger lime mixture, and so 
on, through successive steeps of increasing strength until 
the scarf skin, with its hair, readily yields to the touch, 
which is generally the case in from two to three weeks, 
according to the texture and condition of the hides and 
the temperature of the atmosphere. As in all other tanning 
processes, however, there is a great diversity of opinion ; 
whether the process of liming should be conducted slowly 
in weak liquors, or as quickly as possible in strong 
liquors, is yet an open question. The old tanners used 
to employ very weak liquors, in which the process of depi- 
lation occupied seA^eral — sometimes many — months for its 
completion. Now, however, we have been taught to believe 
that so long a soaking as even three weeks causes a loss of 
gelatine ; some tanners, therefore, prefer using strong 
liquors, whereby they are enabled to unhair the hides even 
in so short a time as about seven days ; and indeed from the 
very nature of the operation — that of removing the cuticle 
and hair chiefly — this method of depilation would appear 
not only the most scientific, but also the most practical, if 
conducted with great care. It is found also that the 
pelts, after treatment in the strong limes, are swollen to 
their fullest extent, and that, after tanning, they give 
greater weight than those which have been treated for a 
longer period in weaker lime liquors. When we reflect 
that the loosening of the epidermis on the one side of 
the skin and the fleshy matters on the other are the 
objects of liming, if this can be effected in such a way 
that the true skin is not subjected to any action of the 
lime it will undoubtedly be an advantage, since the rais- 
ing or swelling can be effected by less objectionable or 
more suitable materials than lime. The nearest approach 
to a perfect system of liming would appear to be that 
which is quickest, for in this case the gelatine of the 
skin is less liable to be dissolved than when subjected 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 117 

for a lengthened period in weak liquor. It almost appears 
contrary to principle to steep hides in spent or weak 
lime at all. 

Properties of Lime. — Before giving the various pro- 
portions of lime employed by different manufacturers, it 
may be well to consider what is the nature of lime and to 
what extent it is soluble in water. "When chalk or lime- 
stone (carbonate of lime) are calcined at a high tempera- 
ture, water and carbonic acid gas are expelled, and oxide 
of calcium, or lime, remains behind. If this lime be again 
exposed to the air, it readily attracts carbonic acid, and 
again becomes converted into carbonate of lime, and 
assumes the form of a white powder. If a lump of fresh 
lime be sprinkled with water, in a few moments a hissing 
and crackling sound is heard, the lime sj)lits up in all 
directions, with evolution of steam, the heat engendered 
being so great as to be capable of igniting wood. The 
lime absorbs about 31"0 of its weight of water, and falls 
into a dry, white powder called hydrate of lime — a chemical 
compound of oxide of calcium (lime) and water. It 
is an ascertained but remarkable fact, discovered by 
Dalton, that lime is more soluble in cold than in hot 
water ; that is to say, water at 60° Fahr. dissolves yfg-, 
while at the temperature of 212° Fahr. (the boiling-point 
of water) it only takes up x .J 7 6 . Mr. E,. Phillips ascer- 
tained that water near the freezing-point took up about 
one-seventh more than water at 60° Fahr., and nearly 
double that of boiling water. 

The solubility of lime at the several temperatures is as 
follows : — 

A pint of water at 32° Fahr. dissolves 13 '25 grains of lime. 
„ „ 60 „ „ 11-6 „ „ 

From this it will be seen that in cold weather the 
strength of the lime liquors (if an excess of undissolved 
lime be present in the lime-pits) will be greater than in 
hot weather. Since, however, chemical action is always 
more vigorous in warm than in cold temperatures, the 



H8 LEATHER MANUFACTURE. 

weaker solutions of lime would be fully as active in sum- 
mer as the stronger liquors in cold weather ; doubtless 
the colder temperatures, however, would be less injurious 
to the pelt. 

As to the proportion of lime which should be employed 
for fifty hides, there seems to be great diversity of opinion. 
While some manufacturers use from 2i to 3 bushels for 
each pit, others have been known to employ more than 
twice as much. About 2 lbs. of lime for each hide is con- 
sidered a good proportion. 

Storing the Lime. — Bearing in mind that lime deterio- 
rates by absorption of carbonic acid from the air, it 
requires to be protected from its influence as much as pos- 
sible. The lime should be kept in a dry closed shed, away 
from contact with timber ; and in order to protect the 
bulk from the air, it is sometimes the practice to sprinkle 
the pile with a little water, to slake the lime on the 
exterior surface, which falls to a powder and acts as a 
covering to the rest of the heap. Another method of 
treating the lime is to place it in a large pit and to slaken 
it with water, and then to cover the whole with a small 
quantity of water, finally covering up the pit with hurdles 
and matting. The thick paste of caustic lime thus formed is 
taken out by shovelfuls at a time as required, and the pit 
again closed. In this way lime is said to be preserved in 
a caustic state for a considerable time, which would doubt- 
less be the case. 

Liming. — There are two methods in practice for carrying 
out the process of liming, namely, 1. The Single Pit Method; 
and, 2. Working in Rounds. In the former, the same pack 
of hides is treated in a single pit, with additions of fresh 
lime from time to time, and in the second the hides are 
first placed in a weak lime or old lime liquor, and suc- 
cessively steeped in stronger liquors, until the epidermis 
yields to the touch. 

Single Pit Method. — The complement of lime and water 
being introduced into the pit, the hides are immersed one 
by one, care being taken to spread them out as flat as 
possible, until the entire number is immersed. After three 



DEPILATION, OR UNHAIRING SKINS AND HIDES. 119 

or four hours they are handled or removed from the pit, 
being piled one over another in a heap, after which they 
are then returned to the pit as before ; after a few hours 
they are subjected to a second handling on the first day. 
The handling is effected by means of blunt-pointed hooks 
(Fig. 7). On the second day, the hides are again drawn, 



Pig. 7. 

and allowed to remain in a heap as before for an hour or 
so, during which time the lime at the bottom of the pit is 
gently stirred or plunged, and the hides are again placed 
in the pit. They are subjected to this treatment during 
the first three or four days, by which time they will have 
become considerably swollen. They are now again drawn 
and placed in a heap as before, and a fresh quantity 
of slaked lime is added and stirred up with the lime 
already in the pit ; the hides are again immersed, and 
the handling and stirring of the liquor repeated once a 
day until the expiration of about twelve or fourteen days 
from the commencement, by which time they will gene- 
rally be in a condition for unhairing. The same lime 
liquors, with additions of fresh lime periodically, may 
be used several times, or until the liquors give indications 
of being charged with ammonia, when the pits must be 
cleaned out. 

Working in Rounds. — This method is much adopted by 
some tanners, and consists in working a series of pits con- 
taining lime liquor of different degrees of strength. The 
green or fresh hides are taken from the water-pits and 
immersed in the old or spent lime-pit, being handled as 
before ; and from this pit they are shifted to the next or 
stronger lime, and so on until they have passed through 
the whole series of three or four pits. Each of these pits 
being strengthened by fresh additions of lime, the last pit 
becomes the first in the next round, and so on until the 
liquors become surcharged with ammonia, when they are 



t2o LEATHER MANUFACTURE. 

cleaned out and recharged with fresh liquor. When this 
system is adopted it is necessary to employ pits close to 
each other to save unnecessary labour. 

Continental Method of Liming. — The method of liming, 
as practised on the Continent, is thus given by Dussauce : 
" In some parts, as in France and Belgium, well-bound 
tubs are preferred. The number of these varies from five 
to twelve, and the solution is then so arranged that there 
is a regular increasing gradation of" density from the first 
to the last, even where the greatest number is taken advan- 
tage of. The first of these, usually called the dead vat, 
contains very little caustic lime, and this is the one to 
which the hides, after washing, are exposed in commencing 
the operation. Here they remain from one to three days, 
according to circumstances, and during this period they 
receive a handling at regular intervals, some twice and 

others three times a day Before the reintroduction, 

the contents of the vat are well agitated, with a view to 
distribute any undissolved quicklime through the liquid, 
so that there be no partial or undue effect exercised on the 
skins. The workmen likewise contrive to spread out the 
latter in the vat as much as possible, and so every part has 
the same exposure to the lime. In the dead vat, however, 
there is very little if any quicklime undissolved. After 
remaining the allotted time in the first vat they are trans- 
ferred to the second, which contains a stronger liquid, or 
more lime, and left in this, with occasional overhauling, 
for a few days, after which they are put into the third, 
and so on, till the hides ultimately arrive at the last vat, 
which contains the fresh lime. In operating in this rota- 
tion, the dead vat of one batch of hides becomes the live 
one of the next, and so on in succession. The time which 
skins take for thorough liming varies according to their 
weight and texture. Thus the lighter skins, as of the 
sheep, are sufficiently acted upon in three to five days, but 
ox hides, kips, and calf-skins require two to three weeks, 
according to the season In many parts of the Con- 
tinent, however, the operations preparatory and conductive 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 121 

to the depilation last two or three months, but in these 
cases the skins are partly swelled, so that, for this special 
treatment, they do not require so much attention in the 
succeeding stages. The quantity of lime which is used by 
the different tanners is somewhat various, and dependent 
upon the size of the hides, but the average is from 18 to 
24 gallons of freshly burnt fat lime — 3 to 4 cubic feet 
measure — for 100 hides of average size." Sometimes hides 
are limed by suspending them from poles in a deep lime- 
pit, whereby considerable time is said to be saved and 
much less handling required. 

Supposed Disadvantages of the Lime Process. — While 
the process of liming hides and skins possesses the advan- 
tages of simplicity and economy, on the other hand, in the 
opinions of some persons, it presents many important dis- 
advantages, which render its employment objectionable. 
This view is held more especially on the Continent. The 
action of the lime is stated to cause a portion of the mem- 
branous matter of the skin — which, were it not removed, 
would enter into the substance of the leather — to be dis- 
solved, whereby a certain loss is sustained. Again, liming 
renders t'he surface of the hide unequal, and by entering 
the cellular structure of the skin, retards the action of the 
tan and causes it to act ununiformly. That this latter 
effect is produced there is no doubt whatever, but as to the 
former, the researches of Dr. John Davy,* conducted at 
Malta in 1829, prove that lime has no injurious action 
upon animal tissues. 

Dr. Davy on the Action of Lime on Animal Matter. — 
" It is commonly asserted and believed that lime exercises a 
corroding, destructive influence on animal matter in general, 
and that animal bodies exposed to its action rapidly de- 
compose and disappear. Accordingly, it has been almost 
invariably recommended to add this earth to graves in 
instances in which rapid decay is considered desirable, as 
on the occasion of the crowding of grave- pits with dead 
bodies during the prevalence of pestilential diseases. From 
* The Chemist, vol. i. New Series, p. 227. 



122 LEATHER MANUFACTURE. 

the results of many experiments which I have made with 
lime on animal substances, I have been compelled to come 
to the conclusion that this opinion is not well founded in 
fact ; indeed, that it is altogether erroneous. The experi- 
ments were commenced in Malta in the summer of 1829, 
and they were carried on during the following year. The 
method observed was to immerse the animal matter for 
trial in cream of lime, or rather a paste of lime, contained 
in a wide-mouthed bottle, well corked and covered with 
cerate cloth to exclude ingress of atmospheric air and to 
preserve the lime in its caustic state. One of the first 
experiments tried commenced on the 27th of August. 
Portions of various textures were immersed, as mentioned 
above. They were taken from a subject in a state of 
incipient putrefaction, and they exhaled a fetid smell. On 
immersion in the lime and water, as might be expected, 
they gave off a strong ammoniacal odour. They were 
first examined on the 24th of September ; they were then 
all in excellent preservation, swollen, but not corroded 
nor their delicate tissue injured." At the expiration 
of seven months, namely in the May following, the 
animal substances were again examined, and were found 
to be much in the same state as before, "the texture 
of each part distinct, and the part, as a whole, easily 
distinguishable." After being left undisturbed for nearly 
two years they were again examined, when considerable 
change had taken place ; the cuticle had become soft 
and transparent, and many other parts had become un- 
distinguishable. 

In a second experiment, " commenced in the beginning 
of October, portions of skin, intestine, cellular tissue, 
muscle, tendon, &c, were similarly treated. The results 
were examined on the 5th of May following. Then, on 
opening the bottle, an ammoniacal, but not putrid, smell 
was perceptible. The parts were found well preserved, 
excepting the fatty matter contained in the cellular tissue, 
which had become opaque, white, and friable, from com- 
bination with the alkaline earth and conversion into soap. 
The tendon was somewhat distended and rendered more 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 123 

transparent, but not gelatinised ; and so also the cutis, the 
last being deprived of its cuticle and hair." Dr. Davy 
found that " after animal substances have been subjected 
to the action of lime, they ceased to be putrescent ; they 
resisted putrefaction, whether placed in air or plunged and 

kept in common water A portion of the cutis 

similarly treated, placed in confined air in a bottle, after a 
whole month emitted no unpleasant odour and appeared to 
be unchanged. I have observed," continues Dr. Davy, 
" that the cuticle, nail, and perhaps hair, are to be excluded 
from the list of animal substances not materially altered 
by the action of lime. On the cuticle its action is power- 
ful, and, I apprehend, in consequence of a chemical com- 
bination between them being formed." 

Dr. Davy finally arrives at this conclusion, as the result 
of a great number of experiments : — " That lime does not 
exercise a destructive corroding power on animal substances 
generally, nor one promoting their decomposition, but on 
the contrary, a preservative and decidedly antiseptic 
power, arresting putrefaction even when commenced, and 
retarding decomposition." 

From the foregoing observations, based upon a series of 
experiments conducted with great care during a period of 
several years, it would appear that however objectionable 
the presence of lime may be if not carefully eliminated by 
bating, by dilute acids, or other means, it has no injurious 
effect upon the cutis vera, or true skin, which, when tanned, 
constitutes leather. Assuming Dr. Davy's deductions to 
be correct, the hypothesis that the liming process, fairly 
conducted, reduces the weight of the hides by acting upon 
and dissolving a portion of the gelatinous tissue of the 
pelt, must be fallacious. It is easy to understand that after 
several weeks' immersion in the lime-pit the fatty matters 
of the hide enter into combination with the lime, forming 
a lime soap, and that the cuticle and even the hair will 
yield to the action of the lime; but from Dr. Davy's obser- 
vations it would appear that the true skin, or pelt, would 
undergo no change whatever in the milk of lime mixture 
in which the hides are by custom immersed. The same 



124 



LEATHER MANUFACTURE. 



cannot, however, be said in respect of hides which are 
steeped for several days in spent or very weak liquors, 
since the solvent action of the water upon the gelatine of 
the hide in these cases would be to a great extent unre- 
stricted. 

Working on the Beam. — When the hides have remained 
sufficiently long in the lime-pits they are examined, and if 
the cuticle readily separates when plucked by the fingers, 
they are taken out and removed to the beam house, where 
they are submitted to certain mechanical operations by 
which the scarf skin, with its hair, is removed from the 
grain side, and the flesh and fatty matter dislodged from 
the flesh side. These operations are termed respectively 
unhairing and fleshing. 

Unhairing. — To accomplish this operation the skin is 
laid upon a convex wooden or iron 
support called the beam (Fig. 8), 
with its flesh side inwards, and 
the beam man then takes a two- 




Fig. 9. 

handled tool, called the unhairing 
knife (Fig. 9), the blade of which 
is blunt, and curved to fit the 
convex surface of the beam. Fig. 10 illustrates the 
mode in which the unhairing is performed. The hair 
is removed very easily by pressing the knife downward 
with moderate force, when the grain of the skin becomes 
exposed. The operation of unhairing a hide is performed 
very quickly, one man being capable of unhairing many 
dozens in a day. 

Fleshing'. — After the hair is removed the hides are fleshed, 
an operation which requires to be performed with more 
care and skill than the last operation, because the knife 
with which it is effected has a sharp edge, and the action 
of the tool is to cut or shave off the fleshy matters, 
whereas the unhairing knife, having a blunt edge, merely 



DEPUTATION, OR UN HAIRING SKINS AND HIDES. 125 

scrapes or rubs the loosened epidermis from the grain side 
of the corium or true skin. In using the fleshing- knife 




Fig-. 10. 

(Fig. 11) the workman has to be very careful not to cut 
away any portion of the true skin, his object being only 
to remove the fat and flesh, so 
as to leave the corium fully 
exposed for the after process 
of tanning. Fig. 12 illustrates Fig. 11. 

the operation of fleshing. 

After unhairing and fleshing, the pelts, as they are now 
called, are thoroughly washed and once more scraped with 
a blunt tool to remove any lime or other matters that may 
still attach to them. This operation is called scudding. The 
fleshings, as they are called, are collected and pressed into 
cakes, and sold to the glue-makers, as also are the ears 
and all projecting parts, which would be useless when 
tanned. The hair was formerly used chiefly by plasterers 
for mixing with mortar, but it is now, after being thoroughly 



126 



LEATHER MANUFACTURE. 



washed and cleansed, employed in the manufacture of 
cheap clothing, blankets, and imitation sealskin. 

It is not always the case that the fleshing is carried out 
to the fullest extent, leaving nothing but the true skin to 
be tanned. Some manufacturers prefer to leave a portion 
of the flesh attached, so that the butts should present a 
more mottled appearance, while some of the American 




Fisr. 12. 



tanners merely have the flesh side lightly scraped, by 
which, of course, greater weight is given to the leather. 
For the finest quality of bark- tanned butts, however, it is 
essential that nothing but the true skin should enter the 
tan pit, and since this, being quite free from fleshy matter, 
is very easily injured, great care is necessary in the 
handling of the pelts in the earlier stages of the tanning 
process. 

Bounding the Pelts. — It was formerly the custom to 
tan the hides whole, after unhairing and fleshing, but the 
system adopted at the present day is to remove with a 
sharp knife all the inferior parts of the pelt, and to tan 
the butts and bends separately. To this end the hide is 
taken by two men and laid upon a table called the rounding 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 127 

table, it is tlien doubled from end to end, grain side out ; 
the head is then removed by a cross cut with the rounding 
knife (Fig. 13) ; the rough edges of 
the tail end are then cut away or . -^^-^ 
rounded, and the sides or bellies are ^- — ..-^ JI^be? 

next cut off, either by one cut or Fig. 13. 

separately. By this method, how- 
ever, the rounder is unable to see those defects, irregu- 
larities, or brand-marks which may be on the under side, 
and consequently cannot trim the hide in such a way as 
to make the best of it. It is, considered a better plan, 




therefore, to lay the hide across^ wooden frame, or horse, 
supported by trestles, the frame*of which forms a tri- 
angular arch. The hides being l«fcl across this, the 
rounder is able to see all parts of the hide, whereby he 



128 LEATHER MANUFACTURE. 

is enabled to perform the operation of rounding with more 
skill and judgment. The accompanying drawing (Fig. 14) 
illustrates by the dotted lines the course which the rounding 
knife should take to separate the various parts from the 
butt, a, or chief part, of the hide, b represents the shoul- 
der, c c the cheeks, and d d the sides or belly pieces. On 
glancing at the somewhat irregular form of the expanded 
hide it will be evident that some judgment must be exer- 
cised in removing the surrounding parts — which are tech- 
nically called offal — from the butt, so as to make the most 
of the latter or more valuable part of the hide. 

After unhairing and fleshing, the hides sometimes pre- 
sent inequalities as to thickness, and in order to render 
them more uniform, or of an average thickness through- 
out, the following plan is adopted, but more especially on 
the Continent : The hides are rubbed with a smoothing 
or polishing stone, which is a tool made of sandstone 
interiorly moulded so as to lie parallel upon the beam, and 
is fixed to a piece of wood furnished with two handles. 
With this the hide is rubbed to bring the parts as nearly 
as possible to an equal thickness. By repeated rubbings 
or scrapings in this way with the stone, alternated by 
washings, the dirt, fleshy parts, and lime are removed as 
far as possible before tanning. 

Depilation by Sweating.— By this method the cuticle 
and fleshy matters are loosened from the corium by a pro- 
cess of putrefactive fermentation, or slow decomposition. 
Although this process is more generally adopted on the 
Continent than in this country, it is employed by some 
English tanners, and is in some respects, if carefully con- 
ducted, preferable to depilation by lime. After removing 
the horns, the hides are piled in heaps for several days, 
after which they are laid across poles in a close apartment 
called a smoke-house, heated somewhat above the ordinary 
temperature by means of a smouldering fire fed with 
spent tan, which produces no flame, or by steam heat. 
In this room the hides undergo a slight superficial fer- 
mentation, by which the cuticle, with its attached hair, 
becomes softened. In France one-half of the hide is 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 129 

first sprinkled with salt and the other half lapped over 
it, to prevent the putrefaction from injuring the tissue 
of the skin. 

In Germany the hides are first piled in a heap and then 
covered with spent tan ; in a short time putrefaction sets 
in, but unless great care is exercised the hides are liable to 
be injured. Another system is to pile the hides on a bed 
of litter, then to cover them with litter, and allow them 
to remain for twenty-four hours, after which they are 
turned over and examined from time to time to ascertain 
if they are fit for unhairing. 

Cold Sweating. — In some parts of the United States 
a system of cold sweating is practised, the hides being 
exposed to damp air in a close apartment. The air is 
kept moist by a spray of water, and it is said that in 
from six to twelve days the hair comes off easily. It 
is further stated that by this method no putrefaction 
takes place, but the loosening of the epidermis is due 
solely to the softening action of the moisture. It is 
obvious, however, that by the above methods the fatty 
matters are not in any degree removed (as is the case in 
the liming process to some extent), consequently these 
must be dislodged by mechanical means on the beam. 
The American system of cold sweating is more fully given 
in another chapter. 

Depilation by Acids. — It has long been known that 
acid liquors have the power of acting upon the roots of 
the hair and cuticle, so as to render them easily detached 
from the true skin. In some tanneries dilute sulphuric acid, 
pyroligneous acid (wood vinegar), fermented barley, rye, or 
bran, or sour milk are used, the latter agent being adopted 
by some Parisian tanners. Rye- water and fermented barley 
are also sometimes employed after the skins have been 
limed, as a substitute for bating. Barley or rye meal in a 
state of fermentation were at one time much used as a 
steep for loosening the cuticle and hair, the active agent 
being the acetic acid formed during the decomposition of 
the vegetable matter. Sulphuric, hydrochloric, and oxalic 
acids have each in turn been employed to loosen the cuticle 



13° LEATHER MANUFACTURE. 

and hair, thereby enabling them to be removed from the 
true skin by the process of scraping- or working on the 
beam ; but tanners maintain that by their employment the 
skins are swelled to such an extent as to injure them 
materially. 

The weak vegetable acids are not excluded from practice, 
more especially in France, Belgium, and parts of Germany. 
Many of the Paris tanners submit the hides, after they 
have been soaked in water, washed, and fleshed, to a number 
of acid vats, in a way analogous to the liming. Generally 
the series of baths consists of five, which from the first to 
the last increase in power and efficacy. The first is usually 
intended to cleanse the hides, the second to soften the hair 
and epidermis for the depilation, and the other three to 
swell and give body to the skins. This operation, which 
is called the white dressing, requires a period of five weeks 
in the summer and six in the winter season. The quantity 
of farinaceous matter which is taken varies at different 
establishments — in some cases 145 lbs. of barley-meal, and 
in others 150 or 160 lbs., are employed. The dressing is 
generally made by leavening one-tenth or one-fifteenth of 
the bulk till it becomes sufficiently sour ; it is then softened 
with hot water, and after the whole has become a thick, 
homogeneous fluid free from lumps, it is added to the 
remaining quantity of the meal in the vat, and tepid 
water in sufficient quantity is poured in to fill the vessel. 
In some cases yeast is added to quicken the fermentation. 
Eight or nine hides are worked in each vat, and as in 
the lime process, the weak or first vat passes in succession 
from one to the other in rotation. The final vat is com- 
pounded of 60 lbs. of meal leavened and thinned with 
water, and left to develop acetic acid for fifteen days. 
In all of these operations, handling and working the 
hides on the beam at regular intervals are indispensable. 
— Dussauce. 

Depilation by Saccharine Matter. — In 1844 Dr. Turn- 
bull obtained a patent for the employment of sugar as a 
depilatory. A solution is prepared by dissolving 14 lbs. of 
coarse sugar in 100 gallons of water, in which the skins 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 131 

are immersed and allowed to remain for eight or ten days, 
being handled in the usual way daily. As soon as the 
hides are sufficiently raised they are removed from the 
sugar steep and allowed to drain, after which they are 
immersed in a strong solution of sea salt, which causes the 
epidermis to contract and become readily detached from 
the true skin. After washing in clean water the hide is 
ready for the tan-pit. It does not appear that this process 
has received much attention, but there is much in its 
favour — more especially at the present day, when sugar is 
very cheap — to merit reconsideration. 

Depilation by Caustic Soda. — This powerful alkali has 
sometimes been employed for unhairing skins and cleansing 
the flesh side from fatty and fleshy matters, which it is 
capable of doing with great rapidity, but extreme caution 
must be exercised in its employment. In order to ensure 
the uniform action of the caustic liquor it is recommended 
either to suspend the hides in the solution or to continually 
handle them while in the pit, otherwise the thinner parts 
of the skin at the edges will be acted upon by the caustic 
liquor while the bulk of the hide may be but little affected. 
The caustic soda is prepared by adding recently slaked lime 
to a boiling solution of ordinary soda crystals in water, 
with brisk stirring. After a few hours' repose the car- 
bonate of lime forms deposits at the bottom of the vessel, 
Avhen the clear solution of caustic soda may be drawn off 
for use.* The solution freely enters into combination with 
the fatty matters of the hide, converting them into soap, 
which may be recovered from the bath or pit when the 
liquor has lost its causticity by adding sulphuric acid to 
the liquor; this, combining with the soda of the soapy 
solution, will set the fatty matters free, which after a 
while will rise to the surface, and may be skimmed off and 
kept in casks for the use of soapmakers. Although caustic 
soda as a depilatory has not been much used in England, 
it is very questionable whether it does not deserve more 
consideration than has hitherto been bestowed upon it. 

* Caustic soda may be obtained in the solid state, as supplied to soap- 
makers, &c, thereby saving the trouble of preparing it. 



*3 2 LEATHER MANUFACTURE. 

Depilation by Bisulphide of Calcium. — This compound 
of sulphur and lime, commonly called sulphuret of lime, in 
the form of a paste, has been employed as a depilatory for 
skins and hides, and if carefully applied is very effective 
and quick in its action. The bisulphide of calcium is pre- 
pared either by passing a stream of sulphuretted hydrogen 
gas into a thick milk of lime, until the latter is super- 
saturated, or by taking equal parts of sulphur and quick- 
lime, and after slaking the lime as usual, boiling these 
substances together in water. The paste thus obtained is 
brushed or painted carefully over the hair side of the hide 
while spread upon the floor. After the hides have been 
well soaked, a light coating of the paste is given, but suffi- 
cient to reach the surface of the skin. Since the sulphide 
would readily destroy ordinary brushes or swabs, we should 
think that brushes might be made with asbestos — a material 
which would not be so readily, if at all, acted upon by the 
caustic sulphide. As the skins are brushed over with the 
sulphide they are laid one above another, hair to hair, 
about twenty in a pile. After about two hours the position 
of the skins is reversed by lifting the uppermost pair and 
laying them by the side of the pack, and upon these the 
other pairs are placed in succession, when the bottom pair 
of the first pack becomes the top pair of the second heap, 
by which a more uniform action of the sulphide is ensured. 
In about four or five hours from the commencement the 
skins are in a condition for unhairing on the beam in the 
ordinary way ; they must, however, be previously soaked 
in cold or tepid water. 

It is stated that although the sulphide is so powerful 
in its action upon the cuticle and hair (which become 
practically destroyed), no injurious effect is produced upon 
the gelatine of the pelt. One serious objection to the 
employment of sulphides in the above operation is the 
highly offensive and injurious odour which these sub- 
stances exhale, and which cannot be long endured by the 
workmen with impunity ; indeed, most disastrous effects 
are known to have resulted from their employment. 

The waste lime from the alkali works, which is bi- 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 133 

sulpiride of calcium in a concentrated form, and also the 
waste lime from the gasworks, which is of the same com- 
position in a less active state, have each been the subject 
of a patent, the latter being stated to unhair the skins in 
from four to eight days. If it be a fact, as stated, that 
the bisulphide of calcium has no effect upon the gelatine 
of which the true skin, or pelt, is chiefly composed, this 
substance should prove more economical than the ordinary 
process of liming, by which a considerable loss of gelatine 
is said to be sustained, although this is disproved by Dr. 
Davy, as we have shown. Since the bisulphide of calcium 
does not raise the pelt, this must be effected by after 
treatment in the dilute acid bath before the hides are sub- 
jected to the tanning operation. 

Depilation by Charcoal. — This process was patented by 
Anderson in 1871. Wood charcoal was applied as a 
substitute for lime, and in much the same way. The hair 
was effectually loosened, but the process was simply one 
of putrefaction, as in the ordinary " sweating " processes, 
while the charcoal acted as a deodorising agent. 

Depilation by Sulphide of Sodium. — For sole leather 
Eitner recommends the following method of applying this 
powerful depilatory : — Dissolve 4 or 5 lbs. of the sulphide 
in each gallon of water. Form this into a thin paste with 
lime or pipeclay. The paste is to be spread evenly over the 
hair side of the hide, which is effected by one workman 
pouring it from a pail down the middle of the hide, while 
another, with a mop or cane broom, rubs it into every part. 
The hide is then folded into a cushion and set aside. In 
from fifteen to twenty hours it will be ready for unhairing, 
when it will be found that the hair is reduced to a pulp, 
and therefore totally destroyed. In the above concen- 
trated condition the hair would, doubtless be destroyed in less 
than an hour. The hides are now thrown into cold water, 
to wash away the sulphide and to enable them to plump. 
The sulphide being highly caustic, it will, if not removed 
by washing, attack the nails and skin of the workmen, 
who should be thoroughly cautioned as to its use, other- 
wise they will soon suffer from " alkaline sores " of a most 



134 LEATHER MANUFACTURE. 

painful character. This method of unhairing gives good 
weight, as also tough and solid leather, but it requires to 
be used with very great care. If not spread evenly upon 
the hide, patches of hair may remain upon the pelt, which 
will be troublesome to remove afterwards. Against the 
advantages derived from the quickness of this process 
must be placed the cost of the material and the loss of 
the hair. Moreover, unless the hides, after being treated 
by the sulphide, are plumped by steeping in weak lime, 
the fleshy matters will be difficult to remove on the beam. 
Raising by acid is also considered necessary, since the 
sulphide itself has but little plumping effect. 

In applying this process to dressing hides, the sulphide 
is used in a more diluted condition, the hides being sus- 
pended in a solution of the sulphide, three-quarters of a 
pound being used per hide. After suspension in this 
solution for about twenty-four hours, the hides are in the 
condition for unhairing, after which they are limed as 
before, to plump or swell them. 

Palmer's Process. — This process consists essentially 
in subjecting hides or skins alternately to the action of 
water and to that of the atmosphere. After the hides are 
cleansed as usual, they may be subjected to this process 
by placing them in an open wheel or cage, which is 
caused to revolve, with its lower portion immersed in 
a tank containing water, whereby the hides are alter- 
nately plunged in that liquid, and as they are raised 
out of the water by the revolution of the wheel, the air has 
free action upon them. This action is kept up until the 
hair or wool is ready to remove. After unhairing, the 
hides or skins are again placed in the revolving wheel or 
cage, and the operation continued until a " dark colouring 
matter can be made to exude from them by ' scudding,' 
when they will be found thoroughly cleansed, softened, 
swelled, and prepared for the subsequent tanning or taw- 
ing by any suitable process." The process is further 
described as follows : " The hides or skins being well 
soaked, are then submitted to the action of the open air 
for about three days, according to the temperature of the 



DEPILATION, OR UNH AIRING SKINS AND HIDES. 135 

atmosphere ; but in no case must it be long enough to 
generate ammonia, as that would indicate incipient decom- 
position, and therefore destruction of gelatine. The hides 
are then returned to the water for about three days, after 
which they are again exposed to the air, and so on, alternat- 
ing the immersion and exposure for about a fortnight from 
the commencement in the case of wet salted hides, when they 
will be found to unhair or unwool readily ; but in the case 
of the harder and drier descriptions of hides the process 
will require to be continued, say, from a week to ten days 
longer. After the hides are unhaired the alternate soak- 
ing and exposure to the air is again repeated, once or 
twice, until, on ' scudding/ the hides are found to dis- 
charge a dark fluid, which I term ' suppressed perspira- 
tion.' As an indication of the time when the hides have 
arrived at the stage when this fluid can be removed, it will 
be found that they give off a very disagreeable effluvium 
(like that which arises from an over-driven beast), and 
different from the ammoniacal smell usually given off by 
hides under treatment. After the complete removal of 
the said dark fluid, the hides will be found to be fresh, 
pure, soft, and sweet-smelling, and they will swell in the 
water and in the subsequent liquors to a better and higher 
degree than hides treated by the ordinary and more 
expensive processes. Such swelling of the hides will also 
indicate the perfect removal of the said dark fluid. The 
atmospheric temperature which I find best suited for 
carrying out my process is about 65° Fahr. If the tem- 
perature be higher, less time will be required, and if lower, 
more time. 

" The hides prepared as above described can be tanned 
in a considerably shorter time than when prepared by the 
known processes, and they will be found to have gained 
from 100 to 112 per cent, in weight, instead of only 
from 65 to 70 per cent., as is the case under the ordinary 
processes of preparing them for tanning. As a pre- 
paratory treatment, the skins or hides may be placed in 
an open drum or cage, which is caused to revolve slowl} r 
with its lower portion immersed in a receptacle containing 



13 5 LEATHER MANUFACTURE. 

water, so that the hides are alternately immersed in the 
water and then subjected to the action of the air, but this 
arrangement need not necessarily be employed, and where 
it cannot be conveniently adopted the hides may be at 
once steeped in tanks for a lengthened time and then 
exposed to the air as described." 

Beck's Process. — In carrying out this process the 
inventor makes a " water stove " instead of a fermenting 
stove, but with this difference, that instead of having a 
hermetically closed chamber, he employs an open vessel, 
as a pan or basin ; he arranges hooks exactly as in the 
fermenting stove, and upon these the skins are suspended 
by the feet, side by side, care being taken to keep them 
perpendicular. The skins being hung up and descending 
nearly to the bottom of the pan, the latter is filled up with 
water until all the skins are submerged. Into this " water 
stove " fresh or beaten skins may be placed. " The pro- 
longed stay of the skins in the water naturally causes the 
peeling, and when this peeling takes place the skin has 
not suffered at all in the water ; on the contrary, it has 
gained in value, and the wool is entirely preserved. 
When the moment for peeling has arrived, it is only 
necessary to empty the basin or pan ; the skins are drained 
separately, and they can be peeled easily. By this water 
system I am also enabled, while preserving the skin and 
the wool, to accelerate more or less the operation of 
peeling. It is preferable to let the skins follow their 
natural course, and cold water may be used both in 
winter and summer. It will be understood that the skins 
take longer to peel in winter than in summer, but no 
harm is occasioned by that. If, on the contrary, it is 
desired to accelerate the operation of peeling, I use tepid 
or hot water, and I add to the bath any material capable 
of hastening this operation, such as soap, soda crystals, 
strained bran, water, &c, provided always that the mate- 
rials employed are not such as would injure either the 
skin or the wool. 

" I may observe that if care has been taken to put the 
Bkins into the water stove perfectly scoured and washed 



DEPILATION, OR UNHAIRING SKINS AND HIDES. 137 

(by means of what is known as the Puech process, for ex- 
ample), wool can be obtained of a value hitherto unknown. 
By my process of peeling the leather obtained is not only 
worth more, but it can be manipulated immediately by 
the tawer, or it may be salted, and more especially it may 
be dried without losing any of its quality." 

The Pullman-Payne Process.— In 1898 Messrs. Pull- 
man and Mr. S. Payne, of Godaluiing, patented the 
method of liming bearing their name, and which appears 
to have been used with a certain amount of success. The 
method depends upon the fact that if a hide which has 
been treated with caustic soda be subsequently treated 
with a solution of calcium chloride, a double decomposi- 
tion takes place and lime is formed in the fibre of the 
pelt, the sodium uniting with the chlorine to form 
common salt. In practice it was found that better 
results were obtained if the hides were first immersed in 
a putrefying soak, this bearing out what was known in 
liming practice that there was some joint action of 
bacteria and the alkaline solution which loosened the 
hair roots in the process. If sodium sulphide is added 
to the caustic soda, the putrefactive soak is not necessary, 
but the hair is likely to be damaged, so that the stale 
preliminary soak is an advantage. The patentees recom- 
mend treating the hides in pits, and according to Procter 
the caustic soda should not exceed a strength of one 
pound in ten gallons (1 per cent). The hides, or calf- 
skins, remain in this for about forty-eight hours, during 
which they are once drawn and returned, by which time, 
if the putrid soaking has been properly done, the hair 
should be fully loosened. The hides are then drained 
for two hours and passed into another pit containing a 
solution of calcium chloride, which should be slightly 
stronger than the caustic soda, say of about one and a 
half pounds per ten gallons. The goods remain in this 
for about forty-eight hours, during which they are drawn 
once, and are then well washed in soft water (free from 
temporary hardness), in which they may be kept for some 
time without injury. 



CHAPTER XL 
BAISING OB SWELLING. 

Raising. — Bating. — The Bate, or Grainer. — The Pure. — Scudding. — 
Sulphuric Acid Bate. — Turnbull's Process. — Warrington's Process. — 
Bating with Barley-meal. — Lactic Acid for Bating. — Formic Acid 
for Bating. 

When the hides have passed through all the foregoing 
operations, the pelts are soaked for a few hours, sometimes 
for many hours, in water, for the purpose of removing the 
lime as far as possible. The more lengthened soaking, 
however, would, we should think, be not only absolutely 
unnecessary, but certainly injurious, inasmuch as the water 
would undoubtedly dissolve a portion of the gelatine of the 
hide, and thus reduce its weight. The next operation to 
which the pelts are submitted is termed raising or swelling, 
in the case of heavy hides, or bating, puring, or drenching, 
as applied to kips and skins, by which the whole or a 
greater portion of the lime is removed from the interior 
of the skin,* the pores become dilated or expanded, and 
the fibrous structure of the skin is thereby rendered more 
susceptible of the action of the tan liquors. 

Raising. — For this purpose Macbride, in the year 1774, 
applied very dilute sulphuric acid (oil of vitriol). The 
hides were immersed for about forty-eight hours in an 
acid solution composed of sulphuric acid 1 part and water 
1000 parts. Since this acid, however, forms an insoluble 
salt of lime (sulphate of lime) when coming in contact 
with the lime absorbed by the skin, its employment for 
this purpose could not, from a chemical point of view, 
commend itself, although it has been very extensively 

* The presence of lime, even in small quantities, not only produces a 
harsh leather, but it also prevents the free action of the tannin. 



RAISING OR SWELLING. *39 

adopted. On the Continent hydrochloric acid has been 
employed for this purpose, and also as a substitute for 
hating, to which we shall have next to refer. A more 
rational system than either of the above has been much 
adopted in France, and has found favour in this country 
with some tanners ; this consists in steeping the hides, in 
the first stage, in spent tan liquors, in which gallic and 
other vegetable acids have been developed during the 
process of tanning. These acids, combining with the 
lime, form soluble salts of the earthy matter, which readily 
become removed from the skin by the spent liquor in 
which they are immersed. In this way the lime is effec- 
tively, if-slowly, got rid of, while the texture of the skin 
suffers no injury. In France sulphuric acid is believed to 
have an injurious effect upon the pelt. 

Bating. — This remarkable and primitive process is 
generally confined to the treatment of kip hides, calves' 
and seal skins, by the light leather tanner, and to the 
skins of goats and other small animals by the skinner. It 
has for its object the removal of the lime, whereby the 
skin acquires the peculiar suppleness and pliancy essential 
to leather of delicate texture. 

The Bate, or Grainer, is essentially a lixivium com- 
posed of the dung of pigeons and fowls in water. In 
this unsavoury mixture the unhaired and fleshed skins are 
immersed for a period of ten or twelve days, or for a shorter 
period in warm weather. By this process of bating, with 
alternate scraping or working, as it is termed, the lime is 
believed to be converted into a soluble compound, and thus 
becomes separated from the tissue of the skin, the mechani- 
cal treatment doubtless aiding the operation considerably. 
Dussauce says : " Investigation has shown that the above 
matters contain an ammoniacal chloride that parts with its 
chlorine on coming in contact with the lime, and so gives 
rise to a soluble combination of this base — chloride of 
calcium — that may readily be abstracted by water. But if 
this is the only result of the noxious process, dilute hydro- 
chloric acid should answer the same purpose. That this 
disgusting method should still continue to be extensively 



140 LEATHER MANUFACTURE. 

practised is disgraceful to modern science. It is stated 
that in London alone £5,000 used annually to be ex- 
pended in collecting and purchasing the above materials 
for the sole use of the tanners of the capital and its 
suburbs. Although this method of bating hides is toler- 
ably effective, j r et it is well known to be attended with 
serious disadvantages, not the least of which is the putre- 
faction of the bate that is going on during the steeping, 
and which injures the hides by acting upon the tissue of 
the skin, reducing its weight in the first instance, and in 
the second rendering it incapable of yielding the quantity 
of leather it should doubtless produce did the above 
changes not occur. Taking the hint from the action of 
the alkaline chloride in this case, some tanners have 
attempted to prevent the putrefaction induced by the 
bating with excrements by avoiding its use altogether, 
using hydrochloric acid in a diluted state as a substitute. 
The innovation has not yet become very general in 
England, although many tanners, especially in Paris, 
are reported to have practised it successfully, the object of 
the expulsion of the lime being satisfactorily gained by it, 
and in addition to this the swelling of the hides also." 

The Pure, which is applied to the skins of the 
lighter kinds of calf, goat, seal, sheep, &c, is prepared 
from the excrement of dogs, but, unlike the bate or 
grain er, which is prepared with cold water, the pure 
employed by the light leather dressers is employed warm ; 
indeed, as hot as the skin can bear without scalding, as it 
is termed. But it is an ascertained fact that the skin of 
the dead animal can bear no more heat than the hand of a 
living human being, without suffering irreparable destruc- 
tion. While immersed in the pure, the skins are re- 
peatedly moved about, and the pureman has to exert the 
utmost caution to prevent the decomposition which ensues 
from injuring the skins. The action of the pure is not 
only rapid but powerful, especially in summer weather. 

Scudding. — The workman forcibly scrapes the skin on 
the beam, which operation is called scudding, by which 
he removes the decomposing agent and the salt of lime 



RAISING OR SWELLING. 141 

(chloride of calcium) formed during the immersion in the 
pure; and in order to prevent further decomposition, 
the pelts are thrown into clean cold water. The 
bating and puring operations — especially the latter — are 
considered the most critical of all the operations of the 
tanner or leather-dresser. The pure, being employed 
warm, accomplishes in a few hours that which the bate 
requires days to effect. The applications of the bate and 
pure will be further considered when treating of light 
leathers and skin-dressing. 

Sulphuric Acid Bate. — Sulphuric acid has also been 
suggested as a substitute for the bate, but while its action 
is not so marked as when hydrochloric acid (muriatic 
acid) is used, it must also be remembered, as we have 
before observed, that sulphuric acid forms an insoluble 
compound with the lime, which no scraping or tvorking 
can entirely remove. This acid, however, in spite of this 
well-known fact, is generally used for raising or swelling 
heavy hides after liming, and before they are placed in 
the handlers in weak solutions of tan. 

Turnbull's Process. — Dr. Turnbull introduced the em- 
ployment of saccharine liquids for the removal of the last 
traces of lime from skins as a substitute for the bate. For 
this purpose 4 or 5 pounds of coarse sugar or molasses, 
dissolved in 60 or 70 gallons of water, formed the bate. 
In this process the sugar forms a soluble saccharate of lime, 
which subsequent soaking and rinsing removes. 

Warrington's Process. — In 1841 Robert Warrington 
patented a process in which carbonate of ammonia was 
employed as a substitute for the ordinary bate for grain- 
ing skins. The carbonate of ammonia, however, although 
it converts the lime into a neutral compound, does not 
eliminate the earthy matter from the hide or skin ; conse- 
quently it fails to promote the necessary suppleness and 
softness of the skin, which are the chief objects of the 
bating process. 

Bating with. Barley-meal. — As a substitute for the 
excrement bate, barley-meal, made into a sour liquor, is 
much used. For 100 lbs. of dry skins, 50 lbs. of coarsely- 



1 42 LEATHER MANUFACTURE. 

ground barley-meal and 5 or 6 lbs. of soured dough are 
taken and intimately mixed with, water. Acetic fermenta- 
tion soon follows, and the acid generated forms a soluble 
salt with the lime in the skins, which becomes removed 
by subsequent washings. 

Lactic Acid for Bating. — Of late years lactic acid has 
come into favour with the more progressive tanners for 
bating or drenching. Its use is more desirable when 
fancy shades are required, as it is stated the skins come 
out much cleaner and clearer than by the old methods. 
This is of much importance, as only the clearest skins 
can be coloured fancy shades, and the fancy shades bring 
a much higher price than the black leather. The usual 
process for chrome-tanned calf skins is to use about half 
a gallon of 50 per cent, lactic acid to 100 gallons of 
water, or if the skins are lightly limed a little less lactic 
acid may be used. The skins are bated in a paddle, and 
water of about 85°-90° Fahr. is used, that is, the water 
is 85°-90° Fahr. after the skins are in. Before they are 
put in, the water should be at least 10° warmer. 

For sheep skins, a little less lactic acid is used than 
for calf skins, and if plump leather is desired, the water 
is somewhat cooler, about 70° Fahr. For goat skins, a 
"pure" is first used, and then the skins are bated in a 
solution of 1 gallon of lactic acid to 400 gallons of water, 
and at nearly 100° Fahr. 

Formic Acid for Bating. — Formic acid is now used 
for de-liming, and also as a preserving agent for sheep 
pelts. An American plan is, after unhairing, to wash in 
a weak solution of acid, using two and a half pints of 
40 per cent, acid to ten hides. After fleshing and wash- 
ing, the pack of hides is then washed in a solution of 
five pints of formic acid in 135 gallons of water, or five 
pints to 1120 lbs. of pelt. The hides are washed until 
de-limed, that is, when a cut section remains white when 
touched with a drop of phenol-phtalein. If the section 
shows a reddish reaction the bating must be continued. 
Formic acid is also used as a plumping agent, and for 
developing " acid " colours in leather dyeing. 



CHAPTER XII. 
TANNING BUTTS FOR SOLE LEATHER. 

Bark Tanning. — Old Methods of Tanning. — Modern System of Tanning. 
— Preparation of the Ooze. The Leaches. — The Handlers. — The 
Layers.— Mixed Tannages. — Tanning hy Suspension. — The Sus- 
penders. — Scouring. — Drying the Tanned Butts. — Old American 
Method. — The Drying Loft. — American Turret Drier. — Working of 
the Turret Drier. — Influence of Light upon Leather. — Striking. — 
Eolling the Leather. — To determine when Leather is Tanned 
throughout. 

Bark Tanning. — While being probably the oldest mate- 
rial used for converting hides into leather, oak-bark 
although hemmed in by a host of competitors, still retains 
its reputation as the best known source of tannin for the 
preparation of sole leather. It is not on account of its 
richness in tannic acid, for there are many vegetable sub- 
stances which yield a far greater percentage of tannin 
than oak bark, but doubtless its great advantages — which 
are most fully developed in the layers — depend upon 
the way in which it is employed. When ground oak- 
bark is stratified between layers of skin deprived of its 
cuticle, hair, and flesh, the whole being saturated with an 
infusion of the bark, not only is the tannin gradually pre- 
sented to the surfaces of the skins, or pelts, and the 
strength of the liquor maintained by the ground bark until 
it is exhausted, but the feeding of the leather with vege- 
table extractive — which is a slow and occult process — 
takes place, whereby the leather is materially increased in 
weight and solidity. 

After the hides have been subjected to all the prelimi- 
nary operations of soaking, liming, unhairing and fleshing, 
rounding and raising, the butts are ready for the tanning 



144 LEATHER MANUFACTURE. 

process; and since this is conducted upon various sys- 
tems, it will be necessary to treat of them separately, 
commencing with the older methods, which, so far as 
regards the excellence of the results obtained, have not 
been surpassed, even though a host of gifted observers 
have endeavoured to hasten the process without injury 
to the quality of the product. It must be understood 
that by the process of raising, the pores of the skin 
become distended or swollen, by which it more readily 
absorbs the tanning principle and its associate, vege- 
table extractive. In this condition the butts are ready 
for the suspenders or handlers, a series of pits in which 
the pelts receive their first dose of tannin from weak infu- 
sions of bark. 

Old Methods of Tanning. — By one of the older methods 
of tanning, the hides were limed in very weak lime 
liquors, and the skins were brought to a condition for un- 
hairing and fleshing in about three months. They were 
then placed between layers of coarsely-ground oak-bark in 
the pits, the layers of hide and bark being alternately 
formed until the pits were full, when a final stratum of 
bark was placed over the whole ; no water or other 
liquor was allowed to enter the pits. After a few weeks 
the hides were transferred to another pit with interposed 
layers of fresh-ground bark, the top hide of the first pit 
being placed at the bottom of the next pit (which was 
previously strewn with ground bark) and so on until the 
position of the whole pack was reversed. After about 
three months the process was repeated, the spent bark 
being substituted for fresh bark each time. These changes 
were effected from time to time until the tanning was 
completed, which generally occupied about eighteen 
months, or even a still longer period. 

An improvement in the above very slow method was 
afterwards adopted with great success. This consisted in 
filling the pits, after they had been filled up with alternate 
layers of hide and ground bark, with soft water; and 
when the tannin was found to be exhausted from the 
liquor or ooze thus formed, the pits were emptied and 



TANNING BUTTS FOR SOLE LEATHER. 145 

again filled with hides and fresh bark, and filled up with 
water as before, these operations being repeated many- 
times during a period of about fifteen months, at the end of 
which time leather of most excellent quality was produced. 

By another method, a layer of spent bark, about six 
inches thick, was first spread over the bottom of the pit, 
and over this about an inch layer of fresh finely-powdered 
bark was placed, and upon this a hide was spread perfectly 
flat ; another layer of fresh bark was spread over the hide, 
then another hide laid above this, followed by another 
layer of bark, and so on until the pit was full ; the whole 
pile was j;hen covered with a six-inch layer of bark, termed 
a hat. This being done, the whole was well trodden 
down and sometimes stout planks or boards, heavily 
weighted, were placed on the upper surface. The pit was 
then filled up with a weak infusion of bark, or ooze, and 
allowed to remain for two or three months, when the pit 
was emptied and the hides were stretched and again 
placed in the pit with alternate layers of fresh bark, and 
the pic again tilled up with ooze as before. After three 
or four months the process was repeated several times, and 
at the last operation the pit was filled with strong ooze. 
In about fifteen months the leather was perfect. 

Sometimes it was the practice, under the older systems, 
instead of filling the pits with water or ooze, to put a 
little water into the bottom of the pit, the vapour from 
which, rising upward, promoted the absorption of tannin 
by the skins. 

Modern System of Tanning. — The practice, under the 
modern system of tanning, is to employ an infusion of 
bark or other tanning material, instead of water, in all 
stages of the process, and ooze of greater strength is used 
than in the older methods, whereby considerable time is 
saved in the conversion of skin into leather. The ooze is 
employed at various degrees of strength, progressively, the 
strongest ooze being reserved for the last operation. The 
tanning strength of the ooze is determined by an instru- 
ment called the barkometer, which is described in another 
chapter. 

L 



146 LEATHER MANUFACTURE. 

In speaking of the modern system of tanning, as 
distinguished from the older methods, we do not wish it 
to be understood that an uniform system of tanning is 
adopted by all manufacturers ; indeed this is so far from 
being the case that it might be more correct to say that 
each manufacturer adopts a method more or less modified 
by his own experience and the discoveries and improve- 
ments of inventors which have from time to time been 
made known to him. And while some manufacturers, in 
every practical art, are more desirous of seeking and 
adopting useful improvements than others, it will 
naturally follow that considerable progress may be made 
in some establishments whilst others continue to work in 
"the same old groove" until successful competition 
renders a change inevitable. Again, the tanner's is a very 
" close " trade, and is conducted with an amount of secrecy 
that almost bars improvement, while it certainly checks 
the progress of the art in this country. Jackson Schultz 
says, with much truth, " When the English tanner shall 
become as communicative as he is at present reticent, the 
whole world will be enlightened as to the economy of 
these agents, with those in use with tanners of the rest of 
the world." This, however, we can scarcely expect while 
our American competitors, in the language of Mr. Schultz, 
" shoot at us from behind a hedge of more than 30 per 
cent, import duty." 

The process of tanning, as generally conducted at the 
present day, we will now describe, but we recommend that 
fair attention should be paid to some of the numerous 
mechanical contrivances described in subsequent chapters 
which have for their object the uniform diffusion of the 
tannin throughout the whole of the pack or series of 
hides in the earlier stages of the operation, as also those 
mechanical devices which have been designed to economise 
the labour of handling. 

Preparation of the Ooze. The Leaches. — This is con- 
ducted in vats or pits termed taps or leaches* These pits 

* Also called letches or latches. 



TANNING BUTTS FOR SOLE LEATHER. 147 

are usually about 9 feet square and 5 feet deep, each one 
being capable of holding sufficient liquor for two handlers, 
or pits in which the pelts are first treated with tan liquor. 
The leaches are commonly fitted with a false bottom, so that 
the liquor may be pumped or drawn off the spent bark as 
required. The ooze is prepared by placing a quantity of 
ground oak-bark in the pit, to which cold water is added, 
and the liquor formed filters through the false bottom, 
fresh water being introduced from time to time until the 
bark is exhausted of its tannin. Some tanners prepare 
their " liquors " or ooze with hot or lukewarm water, by 
passing steam through a large iron pipe to the lower part 
of a deep pit containing a mixture of the bark and water. 
A little above the true bottom is a false bottom, through 
which the liquor filters into the space below, and from 
which it is withdrawn by suitable pumps. Steam pumps 
are now generally employed for this purpose, as also for 
transferring the liquors from one pit to another ; some of 
these pumps are capable of distributing as much as 
13,000 gallons of liquor per hour. By another system, 
water is first applied to nearly exhausted bark, which 
is allowed to remain at a moderate heat for . a consider- 
able time, and the weak infusion thus obtained is pumped 
into a pit containing bark somewhat less exhausted. 
The liquor from this second pit is then transferred to 
a third still richer in tannin, and so on through a series 
of leaches until it reaches a leach or pit containing 
freshly-ground bark, from which pit the liquor is with- 
drawn for use. The liquors or oozes are termed re- 
spectively handler liquor and layer liquor, the latter being 
the stronger. 

The Handlers. — When the butts have passed through 
all the preliminary processes, they are transferred to the 
handlers, a series of pits 7 feet by 5 feet, and 5 feet deep, 
in which they are treated with weak infusions of bark, 
commencing at about 15° to 20° by the barkometer, being 
handled twice a day during the first two or three days, 
either by turning them over in the liquor, or by taking 
them out one by one and piling them in a heap, and 



148 LEATHER MANUFACTURE. 

then replacing them fn reverse order in the pit. The 
operation of handling is shown in Fig. 15. It is more 
generally the practice, however, to work the handlers 
in what is termed a round, which may consist of six 
pits. In the first of the series the washed butts, as 
they come from the beam-house, are placed ; or, when 
susjjenders are employed (to which we shall presently 




Fie. 15. 



refer), those which have received a preliminary treatment 
in these vats. The butts are placed in the first pit, one 
by one, and are handled once or twice a day, by removing 
them from and returning them to the same pit, after 
which they are shifted to the next, and so on, through 
the first four pits ; after which they are treated in the last 
two pits of the series in this way : the butts are spread 
out one by one in the next pit, each butt being sprinkled 
over with a thin layer of finely-ground oak-bark, which 
has the effect of keeping them from absolute contact, 



TANNING BUTTS FOR SOLS, LEATHER. 1 19 

whereby the ooze more readily reaches all surfaces of 
the butts, and at the same time augments the strength of 
the liquor ; moreover, by this system the feeding of the 
skin with tannin and extractive matter is greatly aug- 
mented. After being thus treated, they are allowed to 
remain for about two days, when they are removed, to allow 
the introduction of fresh liquor and powdered oak-bark, 
to which treatment they are subjected about three times 
a week. The other packs follow in due succession, and 
eventually the first becomes the most advanced, while the 
last pack, fresh from the beam-house, becomes the first of 
the next round, and so on. 

When "all the pits have been worked in this way, the 
last pit eventually contains merely the stale sour liquor 
through which all the butts in the round have succes- 
sively passed. This liquor is generally pumped into the 
" suspenders," where such are employed, in which, any 
tannin that may still be present becomes absorbed by 
green or fresh butts, after which the liquor, being ex- 
hausted of its tannin, is run oft' as waste. As each pit 
becomes empty, it is cleaned out and recharged with fresh 
clear liquor or ooze from the leaches, the strength of 
which varies from 20° to 30°, according to the practice of 
the tanner. 

The treatment of butts in the handlers generally occu- 
pies about six or eight weeks, by which time the colouring 
matter of the bark and the tannin should have struck, 
as it is termed, through about one-third of the substance 
of the pelt. By this time the butts of the oldest packs 
will generally have become covered with a peculiar 
bloom, as it is called, and which is ellagic acid, a substance 
insoluble in water ; the substance of the pelt is also 
materially increased in weight, and is more firm and 
solid. In this condition the butts are next removed to 
the layers, in which they receive the final treatment of 
bark and ooze, in progressive stages, until the tanning is 
complete. 

The Layers. — In these pits, which are termed lay- 
away s by the Americans, the butts are stratified with 



ISO LEATHER MANUFACTURE. 

ground oak-bark, which is carefully spread between each 
butt to the depth of about one inch. A layer of bark is 
first spread over the bottom of the pit, and a butt is then 
laid over this, followed by another layer of bark, then a 
butt, and so on until the pit is full, a layer of ground bark, 
called a hat, being placed on the top. The pit is then 
filled up with ooze at about 80° to 35°, more or less, ac- 
cording to the practice of the tanner. The layer is then 
allowed to rest undisturbed for five or six weeks, by 
which time the tannin, with extractive matter, wall have 
combined with the animal fibre. The butts are then taken 
out, and the spent bark and ooze removed, after which 
they are stratified with bark as before, and the pit then 
filled, being in this second layer treated with ooze at about 
40°. At the end of about three months, the butts are 
again shifted, stratified with fresh bark, and treated with 
a still stronger ooze. About the end of six months from 
the commencement, the thinner butts will have become 
perfectly tanned, while the stouter butts will require to 
be treated again with fresh bark as before, with ooze at 
about 60°, or even higher, and in this layer they must 
remain for about six w r eeks or two months. Mr. Schultz 
strongly objects to the practice of working butts of irre- 
gular thickness in the same pack, and indeed common 
sense would support his view, since it is obvious that 
while the stouter butts would be imperfectly tanned, some 
of the thinner butts, being tanned, would probably suffer 
from prolonged immersion in exhausted liquor. 

In shifting the butts from one pit to another, the top 
butt of one pack becomes the bottom butt of the next, by 
which change of position the action of the tannin and 
the effects of pressure become to some extent equalised 
throughout the entire pack. There appears to be no fixed 
rule as to the strength of ooze, or the period of time 
which should be allowed for tanning heavy butts, since 
each tanner adopts a method of his own ; indeed, in this 
as in every other branch of the art, there appears to be 
considerable difference in practice — personal judgment 
rather than fixed rule being the chief guide in most of the 



TANNING BUTTS FOR SOLE LEATHER. 151 

operations of the tanner. A general view of the tan-pits 
is given in the engraving Fig. 16. 

Mixed Tannages. — As to the materials employed in 
butt tanning, there is considerable difference in practice 
at the various tanneries. While some tanners prepare their 
liquors entirely from oak-bark, others use valonia for their 
liquors, and employ ground bark only for sprinkling, or 
" dusting " in the handlers ; other tanners employ two- 
thirds valonia to one-third myrobalans in making their 
liquors, or one-half valonia to one-fourth each mimosa and 
myrobalans. Divi divi is not extensively used in butt 
tanning owing to its liability to induce fermentation ; but 
since it fs a cheap material and is reputed to give good 
weight to the butt, there is a natural desire to employ it 
as far as can be done with safety, with or without the use 
of antiferments. In some tanneries, divi divi is used in 
small proportions with each tap or leach, by placing it 
beneath the other tanning materials, so as to keep it as 
far as possible from the air. If, however, its suscepti- 
bility to fermentation is due to mucilaginous or other vege- 
table matter (which is most probable), its exclusion from 
the air would not, we should think, be of much conse- 
quence ; but its tendency to promote this decomposition 
might be more readily checked by employing one or other 
of the substances which have been found most effective 
in arresting gallic fermentation. 

Valonia is an important tanning material, but when used 
alone it imparts an objectionable colour and harshness 
to the leather; it is therefore most generally employed with 
a moderate proportion of myrobalans. An excess of the 
latter would be mischievous, since they are considered liable 
to promote gallic fermentation. Mimosa is much used to 
modify the colour of valonia, since it imparts an agreeable 
pinkish tinge to the leather which is generally approved. 
Being a powerfully astringent substance, while yielding a 
strong colour, it can only be used in moderate proportions. 
The tannin of this material requires to be extracted by 
boiling water — steam heat being generally employed — 
and the liquors are usually prepared in separate pits. 



TANNING BUTTS FOR SOLE LEATHER. 153 

Mimosa liquors are not so susceptible of gallic fermenta- 
tion as the tannins obtained from some other materials, as 
divi-divi, for example. Grambier, or terra japonica, is fre- 
quently added to the handler liquors in moderate propor- 
tions, and is specially useful in keeping up the tanning 
strength of the liquors. Of the many new tanning extracts 
which are now largely imported into this country, oak- 
wood, chestnut, hemlock, and mangrove are prominent, 
and the two former have now firmly established them- 
selves into favour ; but it will probably be a very long 
time before any English tanner will use — from choice — 
any tanning material but oak-bark for the preparation of 
the best "quality of sole leather. Indeed, while the tan 
colour of oak-bark remains the accepted colour of the best 
English leather, it will be difficult to induce the trade to 
recognise any leather, as of the best oak-bark tannage, 
which presents a different tint to that to which they have 
been so long accustomed. 

Tanning by Suspension. — In some tanneries it is the 
practice to suspend the hides in weak tanning infusions 
before they are treated in the handlers. The object of 
this system is to ensure the uniform absorption of tannin 
by the pelts before subjecting them to the rough usage of 
handling, which in the early stages of the process is liable 
to cause injury to the delicate structure of the pelt. It 
will be readily understood that after the pelt has become 
partially tanned it is less susceptible of injury, and any 
method, therefore, which will effect this object without 
subjecting the delicate texture of the unhaired skin to 
the chances of abrasion, or to the rough treatment of iron 
hooks, must be advantageous. When the hides have become 
partially tanned, the}^ are more capable of bearing without 
injury the rougher treatment which handling, however 
carefully conducted, necessarily involves. 

The Suspenders. — There have been many ingenious 
contrivances introduced for suspending hides in the tan 
liquors, both in the earlier stages of the process and also 
for the complete tanning of hides, the latter of which 
will be described hereafter. In one form of suspender 



154 LEATHER MANUFACTURE. 

a stout wooden shaft is placed across the pit lengthwise, 
being partially immersed in the liquor ; to this shaft about 
20 hides are attached, one above another. When the 
shaft revolves, the first or upper hide becomes lowered 
into the liquor, followed by the second and third, and so 
on, the entire pile of hides becoming unfolded as it were, 
and one by one lowered into the liquor ; as the shaft con- 
tinues to revolve, the hides become alternately exposed to 
the air and the tan liquor. Doubtless it would be an 
improvement if the hides could be kept under the liquor 
the whole time ; still the exposure to the air is only 
momentary, and certainly much less than in the ordi- 
nary system of handling. By this method the butts 
would undoubtedly be constantly exposed to fresh sur- 
faces of tan liquor — a most important point to be reached 
in all processes of immersion in which chemical action 
plays a part. 

The American Rocker Handler, described in another 
chapter, is much adopted in the United States, and is, we 
believe, used to some extent in this country. But although 
in the early stages of tanning, when the object is to im- 
pregnate the skins throughout with a moderate amount of 
tannin, the practice of keeping the hides in motion while 
in the weak* liquors is doubtless advantageous, in the 
latter stages the reverse treatment appears to be accepted 
as that which is most favourable to the proper feeding of 
the hide and the production of good leather. This fact 
was established by the older tanners and recognised by 
Sir Humphry Davy and all observers of eminence who 
had studied the subject. In support of this, Jackson 
Schultz says, " Leather tanned while at rest will have a 
firmer texture than if motion is used to aid the tanning. 
This would probably be the testimony of the butt tanners 
of Great Britain, and there is much in our own experience 
to confirm such a view of the case." Indeed, when we 
reflect that not only tannin but vegetable extractive enters 

* If the pelts were immersed in strong ooze at first, they would become 
ease-hardened, as it is termed, in which, state they would offer great 
resistance to the further absorption of tannin. 



TANNING BUTTS FOR SOLE LEATHER. 155 

into the composition of sound leather, it will at once be 
apparent that this substance — not having the same affinity 
for gelatine as tannin — would necessarily require a con- 
dition cf rest to enable it to combine, even in small 
quantity, with materials which have so powerful an affinity 
for each other. To feed the leather properly, therefore, 
rest during a greater portion of the time required for 
tanning is an absolute necessity in the preparation of 
what is known as leather — that is, not merely a spongy 
compound of tanno-gelatine plus colouring matter, which 
frequently passes under that name, but leather properly 
so-called. 

After the butts are removed from the layers, it is some- 
times the practice to throw them into pits containing weak 
tan liquor, and then to take them out one by one, and 
brush them all over to remove particles of spent tan which 
may have adhered to them ; they are then laid across a 
beam called the horse to drain. It is usual at this stage — 
especially with butts of the best bark tannage — to strike 
them with the pin (Fig. 18) while still moist, to remove 
the bloom ; but sometimes this is effected by laying the 
butt flat on the scouring- table and rubbing it with a 
stone called the scouring -stone, a tool provided with 
two sharp edges produced, by working on a grindstone. 
With this tool the workman removes every trace of 
bloom from the grain side of the leather. The grain 
side is next rubbed over with a damp cloth, then with a 
dry one, and afterwards linseed oil is rubbed over the 
grain to prevent the too rapid drying of this surface of 
the leather. 

Scouring. — This is sometimes effected by scouring- 
machines, one of which, the " Burdon " scourer, is shown 
m Fig. 17. See also Fig. 66, p. 408. After scouring it 
is sometimes the practice to strike the leather with the 
pin. to lay the grain, and after this the grain side is 
oiled, and the butts then sent to the loft, where they are 
hung up and allowed to remain until partially dried ; they 
are then taken down, the flesh and grain sides slightly 
damped, and the butts are next piled in a heap to sam, or 



156 



LEATHER MANUFACTURE. 



samm, as it is termed, for several days, by which the 
leather becomes tempered, or in an uniformly moist and 




Fig. 17. 

softened condition. In this state it is ready for the first 
rolling operation, which will be described further on. 

Drying the Tanned Butts. — Although apparently a 
simple process in itself, much skill and judgment on the 
part of the workman are required to dry recently tanned 
skins properly. If the drying be too slow, especially in 
damp weather, the leather is apt to mould, which is very 
injurious to it ; if, on the other hand, the drying be too 
quick, or the leather is exposed to the direct raj r s of the 
sun, it is liable to become discoloured, hard, and brittle. 
A well- ventilated loft, in which the skins may be exposed 
to a gentle but continuous current of air, without being 
subject to the direct solar rays, is considered most favour- 
able for uniform and perfect drying. 

Old American Method. — The skins, when sufficiently 
tanned, are taken from the pits without being shaken or 



TANNING BUTTS FOR SOLE LEATHER. H57 

beaten, and are stretched on pegs or hung up by their 
heads from large nails, each one being kept expanded by 
two or three sticks passed through from side to side, 
so that all parts may be uniformly exposed to the air. 
When they have begun to whiten, and have become 
slightly stiff, but before they are perfectly dry, they are 
stretched out upon a clean place and scoured with the 
spent tan with which they are still covered. "When well 
cleaned in this way, they are then to be trodden out and 
beaten with the soles of the feet in every direction upon 
both sides ; and after the inequalities and protuberances 
of surface Lave been made to disappear by the flatten- 
ing process, they are assorted in sizes and piled up in 
heaps. While the skins are stretched in the drying- 
room they should be beaten twice daily, morning and 
evening, upon the flesh side with a round-faced wooden 
mallet. If the skins should be dry, the operation may be 
facilitated by moistening their surface with a wet brush. 
This process imparts firmness, but the operations are now 
almost entirely done by machinery. 

The Drying Loft, or Shed, as it is sometimes called, 
is a capacious wooden structure, one or more stories high, 
according to the extent of the works. It is provided with 
a series of openings all round the apartment, through 
which the wind from any quarter can pass freely, and 
thus traverse through the suspended hides. These openings 
are protected by weather-boards, or trap doors, which can 
be placed at such an angle that while the air maybe admitted 
as required, the direct rays of the sun can be prevented from 
reaching the leather. The circulation of air is further 
aided by a portion of the flooring being composed of 
narrow boards placed at a certain distance (about 2 inches) 
apart from each other, whereby air is admitted from 
below as well as at the sides and ends of the shed. To 
facilitate the drying, especially in cold and damp weather, 
a series of 4-inch flanged iron pipes, for steam or hot air, 
are fixed above the floor, this range of piping extending 
all round the interior of the shed. These pipes are fre- 
quently heated by waste steam from the boiler. Although 



158 LEATHER MANUFACTURE. 

this system of artificial drying is by some persons be- 
lieved to be injurious to the leather, on the ground 
that the heat dries the air, it must be borne in mind 
that the moisture given off even from merely damp 
hides would be amply sufficient to compensate for the 
natural moisture expelled by the heat from the steam- 
pipes. "When the drying of the hides is near completion, 
however, greater caution would undoubtedly be neces- 
sary in subjecting them to the continued action of hot-air 
pipes. 

The hygroscopic condition of the air — that is, the presence 
or absence of moisture — may be determined by means of an 
instrument called the hygrometer, of which there are several 
different forms. " Mason's hygrometer shows the relative 
dryness and moisture of the atmosphere by the degree of 
cold produced by evaporation from a given surface. If 
two delicate thermometers have their bulbs covered with a 
thin piece of muslin, and if the one be dry and the other 
moist, the depression of the latter will be directly as the 
rapidity or amount of evaporation, and this again will 
chiefly depend upon the state of the circumambient air as 
to moisture ; if it be charged with vapour, no evapora- 
tion from the wet bulb will ensue, and consequently the 
mercury in that thermometer will remain stationary ; if, 
on the contrary, the air be very dry, it will eagerly ab- 
stract vapour from the humid surface, and a corresponding 
degree of cold will be indicated by the depression of the 
mercury in the humid thermometer as compared with the 
standard or dry thermometer." — Brande. 

To roughly determine whether the drying of the leather 
is complete in an apartment heated by steam or hot-air 
pipes, a small pocket looking-glass, previously kept in a 
very cold situation, might be used. If the glass be held 
about half an inch from, or nearly touching, the suspended 
leather, if moisture be still given off from its surface this 
will be at once condensed on the face of the glass, as if 
it had been breathed upon ; if the reverse is the case 
(provided that the glass be cold) it may be concluded that 
the leather is perfectly dry. 



TANNING BUTTS FOR SOLE LEATHER. 159 

In some tanneries the drying sheds have been heated 
by hot-water apparatus in place of steam, and we believe 
with success. 

About 6 feet above the floor of the drying-loft a series 
of rafters are fixed, and upon these are laid the wooden 
poles, called "shed poles," from which the hides are 
suspended. These poles are simply timber from which 
the bark has been removed ; they average about 2|- inches 
in thickness, and are from 6 to 8 feet in length. 

American Turret Drier. — A brief description of the 
American "turret drier" will prove interesting to those 
who may \>e desirous of modifying their present method of 
drying, or may require an extension of their present drying 
arrangements. The following is abridged from Mr. Jackson 
Schultz's admirable description of the turret drier : The 
building may be any number of stories high, some being 
three or four, while others are seven or eight. Mr. 
Schultz, however, recommends but five stories, each about 
7 feet clear between the beams, or high enough for a man 
to pass with his hat on. Such a building need not be 
made of very heavy timber, and therefore would be in- 
expensive as compared with higher structures. The 
building should be about two spans of timber — say 40 feet 
— wide, with two rows of posts equidistant from the sides. 
Longitudinally with these rows of posts should run a light 
board partition, with intersections at every 10 feet, ex- 
tending to the sides. This would cut the space up into 
two rows of rooms about 10 by 12 feet each, with a centre 
passage of about 13 feet. The roof is made of the usual 
latticed lantern form from end to end. All the floors 
above the ground-floor should be latticed, and the rooms 
would of course be immediately above each other, so that 
if the building were five stories high, there would be five 
rooms, 10 by 12 each, standing one above another, and 
there should be just as many of these rooms as would dry 
the stock of the yard. The centre passage-ways should 
be lighted by cross--sections leading to the windows, and 
each room should contain one small window close to the 
top to admit light only. There should be no openings 



160 LEATHER MANUFACTURE. 

except at the base of the lower room, with the air leading 
directly on the piping. 

Each room will hold one pack of 100 or 120 hides, 
depending upon the weight of leather, and will dry the 
same in ten days. The rooms on the first floor should be 
supplied with steam-pipes laid on the floor, or raised 
only a few inches above it. The heating of the pipes 
should be under separate control, so that any degree of 
heat can be admitted, and the steam turned on or off at 
pleasure. 

Working of the Turret Drier. — All the packs taken 
out in one day, or in two or more days in succession, 
should go into one of these sections, so that the condition 
of the leather may be as nearly uniform as possible in each 
set of rooms. The leather is hung upon sticks, in double 
rows, leaving a passage of nearly two feet between. No 
steam should be allowed to enter the pipes or the section 
during the first three or four days, neither should the 
trap-doors, which lead outwardly, be opened but slightly 
except in warm weather, or when the wind blows high ; 
but in autumn, or during overcast weather, the lower 
trap-doors may be safely left open. About the third or 
fourth day a low degree of steam heat may be applied, 
and gradually increased until the seventh to the tenth day, 
by which time the leather should be fully dried. All the 
hides in both tiers and in all the five rooms will have dried 
in about the same time, and may be replaced by others. 
Mr. Schultz says, " One of the best guides that I can give 
for the capacity and practical working of these driers in 
connection with a tannery is this : one of these sections 
should be large enough to hold one-tenth of ten days' 
work. I have known turrets so actively worked as to 
turn out stock in seven days ; but I prefer ten, since it is 
very important not to hurry the drying during the first 

few days The turret drier is, beyond all question, 

the most efficient and artistic method yet devised for 
drying leather, and, in some of its modified forms, should 
be adopted by all tanners. The difference in the tempera- 
ture at the ground and at an altitude of 40 or 50 feet 



TANNING BUTTS FOR SOLE LEATHER. 161 

would of itself create a draught, as is well illustrated by 
the erection of stacks or chimneys for the passing off of 
smoke or gas. But, if to this natural action of the differ- 
ence of temperature we add a little steam heat, a steady 
yet moderate circulation will be maintained from the 
bottom toward the top or opening of this structure, carry- 
ing upward and off the dampness from the leather, without 
creating such violent currents of air as to stain and injure 
the colour." 

Mr. Schultz says that it is believed that the principle 
of the above method of drying sole leather could be 
applied with equal advantage to all other kinds of 
leather ; and indeed, when we consider that the gentle 
motion of the heated air — constantly ascending as it 
does from the steam-pipes — must keep up a continued 
circulation of the air within the drying-rooms, this 
should be the most favourable condition under which even 
the most delicate leathers could be dried, provided that 
the temperature were kept as low as possible to effect the 
object. 

For the purpose of conveying the hides to and from the 
drying-rooms, lifts or elevators are employed, which may 
be of any approved construction ; but Mr. Schultz speaks 
very highly of an endless chain elevator which he strongly 
recommends to all tanners. This consists of an endless 
chain, running from the extreme bottom to the top floor, 
ending under the roof. The chain runs in a wooden box 
enclosed on three sides. The open or outer side serves to 
attach the hides by means of hooks fixed to the links of 
the chain at a distance of about 4 feet. The distance 
between the attaching hooks should be sufficient to enable 
the workmen to attach below, and take off above, the sides. 
By this simple method leather may be elevated with no 
more actual expense than if dried on the ground-floor, and 
l the hides, when once hung, remain until fully dried, thus 
j saving all the expense of " shifting," &c. 

Influence of Light upon Leather. — The influence of 
light upon the colouring matter and juices of vegetable 
substances is well known ; and while this is not so marked 

M 



162 LEATHER MANUFACTURE. 

when such matter is diffused through the cellular structure 
of the plants — by which it is protected from the action of 
light in some degree — if the vegetable substance be cut or 
otherwise injured, a discoloration or darkening of the part 
takes place rapidly afterwards. This is very noticeable 
when we remove the epidermis or bark from a growing 
plant ; the exposed surfaces soon assume a darkish colour, 
which increases in depth by further exposure. Probably 
absorption of oxygen may also influence the result. The 
fact is specially recognisable in the case of the walnut, the 
green covering of which is well known to impart a deep 
brown stain to the fingers. The same may also be said of 
young potatoes, in removing the skin from which the 
domestic servant frequently finds the tips of her fingers 
embellished by a brown stain. Now in the preparation of 
oozes, or infusions of bark, the ground material, fresh 
from the mill, is steeped in water — either warm or cold — 
and while the tannin most readily enters into solution, 
vegetable extractive and colouring matter also become dis- 
solved in the menstruum. Now, what we wish to suggest 
as the cause of the newly tanned leather becoming dark- 
ened by exposure to air and strong light is this : that the 
vegetable tissue in which the greatest amount of astrin- 
gent property lies (the part which was nearest the wood) 
also contains colourable matter which has not yet been 
fully exposed to the action of strong light, and that an 
infusion of this matter must, in the ordinary course of 
things, become darkened by exposure to light. And further, 
that when hides are steeped for a more or less lengthened 
period in such infusion, the leather produced must be 
acted upon and become discoloured, or darkened in colour, 
by exposure to light, more especially while in a moist 
condition. 

Schultz says, " Leather dried in the open air will cer- 
tainly dry dark, even if tanned with pure oak, and if 
tanned with hemlock, or a mixed bark, will darken to a 
damaging extent. If currents of air reach the leather 
while in a wet state, a like result is produced, with the 
addition of great harshness of grain. If a bright light, 



TANNING BUTTS FOR SOLE LEATHER. 163 

particularly if the sun's rays reach the grain or flesh, the 
acid of the leather turns brown, and is permanently dis- 
coloured. The influence of the direct raj^s of the sun, or 
even the strong light of the sun, on vegetation is a good 
illustration of these influences on the colour of leather 
containing vegetable acid in solution. The ordinary table 
celery is covered with earth as fast as it grows to the 
surface to keep the light from it, so that it may be white 
and tender. Grass that grows under cover, excluded from 
light, is white, not green. This law of light applies to 
ail vegetation. Availing ourselves of this principle of 
light, we say that leather that is intended to be fair should 
be dried in the dark, and as free as possible from currents 
of air." 

Although, as we have said, we believe that light has 
a powerful influence upon the vegetable matter absorbed 
by the hide, we believe that the oxygen of the air also 
plays an important part in this discoloration, or rather 
coloration, since from the examples we have given, 
light alone could scarcely have produced the effect. The 
scratched rind of the green walnut produces an almost 
instantaneous stain, which may be partially, if not 
wholly, due to oxidation ; while the celery referred to 
by Mr. Schultz would doubtless (if not protected by earth- 
ing up) acquire its natural green colour by the action of 
light only. 

Striking. — When the hides are partially dried, as we 
have before observed, they are submitted to the operation 




Fig. 18. 

known as striking, which is accomplished with the striking- 
fin (Fig. 18) a two-handled tool of triangular form present- 



164 



LEATHER MANUFACTURE. 



ing three blunt edges. A section of the blade of the tool 
is also shown. The butt is thrown across a horizontal convex 
beam, called the horse, and the workman, taking the tool 
by its handles, presses it firmly over the grain side of the 
leather, until the entire surface has been gone over. 
Fig. 19 represents a workman in the act of striking a butt. 
To economise labour in this operation several forms of strik- 




ing. 19. 

ing-machines, worked by steam, have been introduced. 
The accompanying drawing (Fig. 20) represents the 
striking-machine of Messrs. Huxham and Browns, and 
Fig. 66 that of Messrs. Wilson, the latter being generally 
used in British yards for butts and bends. It is stated 
that leather struck in these machines acquires a solidity 
and firmness superior to that of hand work, while it also 
enables the tanner to do with less rolling. The workman, 
by a weighted adjustable foot lever, regulates the pressure 
instantaneously, so that no part of the leather remains 
untouched. Although hand striking is still much applied, 
there can be little doubt that in this, as in many other 
operations of the tanner, machinery, from the rapidity 



TANNING BUTTS FOR SOLE LEATHER. 



i65 



of its action, will eventually supersede hand labour to 
a great extent. 




Rolling the Leather. — When the butts are partially- 
dried, they are submitted to the first operation of rolling. 
For this purpose hand or steam rollers are used. The 
hand machine consists of a brass cylinder or roller, sur- 
mounted by a heavily weighted box-truck, and furnished 
with a long handle. The butt is laid flat upon a solid and 
level wooden bed coated with metal (zinc or brass being 
generally used), and the workman passes the roller back- 
wards and forwards until every part of the butt has been 
repeatedly passed over. Fig. 21 shows the method of 
using the hand roller. After the first rolling, the butt is 
again hung up to become further dried, when the oiling 
and rolling are repeated, and if necessary, the two surfaces 
of the butt are moderately damped each time before 
repeating the rolling. There are many ingenious and 
effective machines for steam rolling, which, as will be 
readily understood, effect a great saving in labour, besides 
being more uniform in their action than could be expected 



1 66 



LEATHER MANUFACTURE. 



from the smaller or hand machine. In Fig. 22 is shown 
a rolling-machine as supplied by Huxham and Browns. 



mm 




Fig. 21. 



The roller is hung upon strong springs, which allows it 
to adjust itself to inequalities in the thickness of the 




Fig-. 22. 



leather. "When in use, the leather is laid flat on an 
ordinary zinc or brass bed, as in hand rolling, and the 



TANNING BUTTS FOR SOLE LEATHER. 



167 



roller passed oyer it, so as to avoid the stretching and 
cockling of the leather which it is said some machines 
are liable to cause. Fig. 23 represents the American 
Pendulum Roller. It is said to be especially suitable for 
leather requiring heavy rolling, such as buffalo, kip hides, 
&c. Speaking of this machine, Schultz says that it is 
claimed that if used at its full pressure the machine has a 
sufficient power to actually cut the leather in half. It is, 




Fie-. 23. 



however, fitted with adjustable spring bearings, enabling 
the roll to adjust itself to unequal thicknesses in the 
leather, and the pressure may be regulated at will. 

To determine when Leather is Tanned throughout. — 
This is ascertained by making a clean cut with a sharp 
knife in the stoutest part of a butt, when, if the tanning 
is complete, the leather exhibits an uniform colour 
throughout its entire substance ; if, on the contrary, a 
light-coloured streak is visible in the interior, the process 
is not complete, and the butts must be submitted to 
further treatment in the layers until the proper point is 
reached — a perfectly uniform colour throughout the entire 
substance of the skin. Beyond this point, however, the 
further steeping of the butts can do no good, and may 
therefore possibly do mischief in proportion to the length 
of what may be termed unnecessary time they may be 



1 68 LEATHER MANUFACTURE. 

immersed in the tan liquor. The aim of many tanners 
appears to be to ensure a good bloom upon their leather — 
as a guarantee, we presume, that it has been bark-tanned 
by a gradual and not by a quick process ; but when the 
perfect and complete tanning is effected, protracted 
immersion in the pits, merely to increase the deposit of 
ellagic acid or bloom, to give an appearance to the 
leather which cannot enhance its durability, would appear 
a mistaken practice, and one which the American tanners 
— who are making great progress in the art — seem to 
ignore. 



CHAPTER XIII. 

TANNING PROCESSES. 

The first English. Patents for Tanning. — Newton's Tanning Process. — 
Aldrich's Process. — Orgereau's Process. — Jennings's Process. — Bal- 
latschano and Trent's Process. — Lomas's Process. — Michel, Kollen, 
and Hertzog's Process. — Keasley's Process. 

As in the case of every other art, innumerable patents 
have been obtained, both at home and abroad, for improve- 
ments in the processes of tanning, and for the machinery 
and implements employed therein, besides many others 
for inventions more or less connected with the manufac- 
ture of leather. It is of the greatest importance to those 
who pursue an art or manufacture that they be acquainted 
with such modifications of the ordinary methods of work- 
ing as may be likely to render their procedure more facile 
or more economical, or otherwise tend to render their 
manufacture more perfect in its results. With this view 
we have selected from the lengthy roll of patented inven- 
tions certain processes which we hope may prove in some 
degree interesting and useful. While refraining from 
making any comments upon the merits of any of these 
processes, we may indulge a hope that from some of them 
at least may be gleaned a fair amount of useful in- 
formation. 

The First English Patents for Tanning. — As speci- 
mens of the orthography of the seventeenth century, the 
following quaint titles of specifications may prove inte- 
resting. The first patent for improvement in leather was 



170 LEATHER MANUFACTURE. 

obtained by John Jasper Wolfen, and is dated December 
8th, 1627. It runs as follows : — 

" A newe invention for the making and pparing of 
etaine stuffs and skynns to hould out wett and rayne." 

In 1635 Christopher Hunt obtained a patent for a 
" ISTewe invention by way of i ymbrodering or hufling of 
guilded leather upon several grounds fitt for hangings or 
other furniture for houses.' " 

In 1660, Charles Howard patented "A newe way for 
the tanning, tawing, dressing, and pparinge all sorts of 
rawe hydes and skinnes into leather in lesse time and with 
lesse charge then formerly hath bin vsed." 

Newton's Tanning Process. — The object of this pro- 
cess is to hasten the operation of tanning by employing 
certain earthy or metallic salts in combination with vege- 
table astringent matter, by the joint action of which it is 
said the combination of the albuminous matter of the 
skin with the bases is promoted. "When other matter 
than catechu is used, the latter, of good quality and con- 
taining 50 per cent, of tannin, is taken as a standard for 
regulating the proportion of the former. The skins must 
as usual be unhaired and free from lime. For treating 
100 calf-skins the following formula is given : — 

Alum 20 lbs. 

Salt 10 „ 

Catechu 100 „ 

Sulphate of alumina 4 „ 

The latter salt may be used either alone or mixed with 
2 lbs. of common salt. The three mixtures are dissolved 
in water in separate vessels, and kept apart. The following 
directions are given for applying the various solutions: 
put into a vat one-fifth of the first solution, one-tenth of 
the second, and one-fourth of the third ; immerse the 
skins in this liquor, handle and stir them repeatedly for 
a short time, then take them out. Now refresh the vat 
by the addition of one-fifth of the first solution, one- 
tenth of the second, and one-fourth of the third. .Replace 
the skins in this mixture ; treat as before, but for a longer 



TANNING PROCESSES. 171 

time. Hemove the skins a second time, refresh the vat 
with one-fifth of the first solution, one-tenth of the second, 
replace the skins in the vat, and allow them to remain for 
some time, handling occasionally as before ; remove them 
again, and mix in the vat the residue of the first and 
third solutions, and one-fifth of the second. Replace the 
s'vins in the vat, and a few days after take them out and 
add to the vat the remaining two-fifths of the second 
mixture. Four or five weeks are sufficient to complete 
the tanning. 

The above process may be modified by laying the skins 
in a vat and stratifying them with 3 lbs. of moistened tan. 
Other skins can be thus tanned, but the proportions must 
be varied, as shown below : — 

For 100 goat skins, take — 

Alum 10 to 12 lbs. 

Catechu 50 to 60 „ 

Salt 6 „ 

For 100 cow hides, take — 

Sulphate of alumina 40 to 50 lbs. 

Salt 20 to 25 „ 

Catechu 500 „ 

For ox hides, per hide, take — 

Sulphate of alumina 14 to 16 lbs. 

Salt 8 „ 

Catechu 60 to 70 „ 

Aldrich's Process. — It is well known that when green 
hides have become dry the surface of the flesh side becomes 
hard or "flinty/' and this condition is a source of much 
trouble to the tanner, and necessitates severe mechanical 
treatment to render the hides sufficiently soft to undergo 
the several processes which convert them into leather. 
Upon this subject Dussauce makes the following observa- 
tions : " As a green hide becomes dry, by evaporation of 
its liquid, the flesh side absorbs oxygen from the atmo- 
sphere, which, combining with the fresh fibro-gelatinous 
surface, forms a hard flinty scale. To free the hide from 



172 LEATHER MANUFACTURE. 

the scale, and facilitate its softening, tanners submit it to 
hard beam breaking, or to the action of a hide-mill, both 
of which have the detrimental effect, to some extent, of 
disturbing the uniform relations of the interposed gelatine, 
and loosening the small bundles of fibres composing the 
structure of the hide, thereby weakening the hide in its 
textile strength ; nor have any of the modern soaks proved 
less detrimental, depending as they do upon a putrefactive 
condition (sweating). The first effect of such soak is to 
decompose the parts of the hides easiest effected, generally 
the fibro- gelatinous structure immediately beneath the 
scale ; hence the frequent water peltings and running of 
hides in the soak, particularly in warm weather." 

As a substitute for the ordinary mechanical treatment 
and soakings, which are thus so clearly shown by Dussauce 
to be mischievous to the structure of the hides, Mr. 
Aldrich, of St. Louis, U.S.A., devised a chemical process 
by which it is said the hides may be rendered as soft and 
pliant as when first removed from the animal. 

Aldrich's process for the treatment of dry flint hides is 
thus given : — 

The hides are first soaked in clear water until pliant ; 
they are then placed in an acid bath composed as follows : — 

Acetic acid . 1 part. 

Water 16 parts. 

In from 24 to 36 hours the above solution will dissolve the 
scale, by combining with its oxygen, and swell the fibres of 
the hides, when they are to be immersed in the following 
bath : — 

Carbonate of ammonia 1 part. 

Water 70 parts. 

This solution, having a strong affinity for the acid 
absorbed by the hide from the first bath, saturates it in 
from 48 to 72 hours, leaving the hide in a naturally pliant 
and soft condition, and so perfectly transformed from a dry 
to a green condition that no tanner can detect the slightest 
difference between stock tanned from dry hides so prepared 



TANNING PROCESSES. 173 

from tlie green hides. The first cost of the acid solution 
is two cents per gallon, or twenty dollars for a large pool 
full, after which it can be used continually, attended with 
no expense except pumping up and passing it through 
the apparatus to renew its strength after it has been used. 
The second solution is prepared from all bate water, and 
is attended with no expense but pumping. 

The above process is said to obviate all danger of damage 
from taint or running, for its action is so perfectly anti- 
septic that hides so softened may be kept for weeks in 
water before being placed in lime ; also by keeping fibrous 
and flanky hides in the first bath double the ordinary time, 
they will plump up and be materially improved, and all 
without any breaking whatever. 

Orgereau's Process. — The object of this process is to 
shorten the time usually occupied by the tanning process, 
and which is effected by a systematic arrangement of the 
materials employed. The skins are submitted to the 
usual operations of depilation and raising, and are then 
placed, in alternate layers of tan and skin, in a vat with a 
perforated false bottom. This vat being about three- 
fourths full, is drenched with water for the first operation, 
and with weak tan liquor for the succeeding operations. 
The liquid slowly penetrates into the mass, and after 
having moistened the contents of the vat, runs through 
the false bottom into a reservoir, from which it is convej^ed 
back to the surface of the materials. The inventor em- 
ploys six vats, each containing 100 native or 120 imported 
hides. The liquid passing into the reservoir is daily dis- 
tributed over the surface of the materials in the vat by 
means of a pump. This operation is continued for one 
month, at the end of which time the vat is emptied and 
the spent bark replaced by fresh bark, and the same pro- 
cess of infiltration repeated. A third operation is neces- 
sary to obtain a proper tanning. The entire process 
occupies four months, and the leather produced is stated 
to be equal in quality to that obtained by the old method ; 
100 parts of dry Buenos Ay res hides yield, by the above 
process, 150 parts of leather. It may be mentioned that 



174 LEATHER MANUFACTURE. 

the inventor of the above process is an eminent Parisian 
tanner. 

Jennings's Process. — In applying this process to thick 
ox hides, they are first unhaired in the usual manner, 
either by steeping them in a lime bath, or by the more recent 
process of sweating. If lime has been used, the hides are 
steeped in dilute hydrochloric acid after they have been 
dehaired, and then washed. This operation proves and 
fits them for the succeeding operations. They are now- 
piled in batches of a dozen hides each, with a hurdle or 
wicker between each pair ; they are then alternately 
lowered into tanks filled with the following solution : — 

Tank No. 1 is charged with a strong solution of alum, 
to which 10 per cent, each of sulphuric and hydrochloric 
acids are added. 

Tank No. 2 is charged with a concentrated solution of 
soda ash, to which is added 5 per cent, of tungstate of 
soda. The skins or hides are immersed six hours at a 
time in these tanks, then withdrawn and drained, and 
transferred alternately from the first to the second tank, 
and vice versa, until the hide is sufficiently hardened. 
The condition of the hide is known by cutting a small 
piece off with a knife. At this stage they are immersed 
for six hours in a strong solution of tungstate of soda 
alone, then lifted, drained, and placed in a liquor of soap, 
made by dissolving 20 lbs. of soap in every 10 gallons of 
water, and the hides agitated in this until the strength 
of the soap is exhausted by being absorbed by the 
hide. They are now washed in soft water, and finally 
steeped for twenty-four hours in a common liquor of oak- 
bark, after which they are dried and finished in the usual 
manner. 

Ballatschano and Trent's Process. — This is one of 
the numerous quick processes, and is thus briefly described : 
In the treatment of horse hides, more especially, by this 
process a considerable increase in substance is said to be 
obtained. The hides are treated with the following tan- 
ning compounds, either singly, or in a certain order, or 
mixed together according to the kind of hide, its thick- 



TANNING PROCESSES. 175 

ness, and the various purposes to which, it is to be applied. 
The compounds employed are : 1. A solution of chromate 
of alumina in pyroligneous acid (wood vinegar) in the 
proportions of about 1000 parts of water to 20 or 30 parts 
respectively of the chromate and acid. 2. A concentrated 
solution of argol,* to which is added a small quantity of a 
protoxide (such as nickel) in ammonia. The argol bath 
is said to have the property of considerably increasing 
the substance of the hides after treatment in the bath 
of pyroligneous acid and chromate of alumina, if the 
hides, after being removed from this bath and rinsed, are 
treated, while still wet, with the solution for twenty-four 
to forty -eight hours, or longer. The patentees state that 
the hides treated with the argol bath " are rendered so 
sensitive to vegetable tanning agents that a bath of 1 
part tannin in 1000 parts of water and 20 parts of pyro- 
ligneous acid will tan a hide in thirty days, whereas a 
hide not treated with the argol bath will, with the excep- 
tion of the brown colouring, show no trace of tanning 
under the same treatment." Tanning with the above 
ingredients may be effected in various ways. Thus, if 2 
parts of solution No. 1 are mixed with 1 part of solution 
No. 2, the tanning of thick ox and horse hides can 
be completely effected in the mixture in from eighteen 
to twenty-one days. When possible to maintain the 
bath at a constant temperature of from 72° to 82° Fahr., 
the tanning can be more quickly effected. The raw 
hides to be tanned by this process are to be prepared in 
the usual way. 

According to the purpose to which the finished leather 
is to be applied, different mixtures of both solutions, 1 
and 2, are employed. For example : — a, 2 parts solution 
No. 1 and 1 part solution No. 2 ; b, the hides are first 
treated with solution No. 1, and then for any desired 
length of time with solution No. 2 ; c, the hides are 
merely treated with solution No. 1. A small quantity of 
carbolic acid is recommended to be added to the baths. 
The hides treated by the above process must afterwards 
* Crude bitartrate of potash, as deposited by wine. 



176 LEATHER MANUFACTURE. 

be carefully washed and then finished in the usual way. 
Before tanning, the hides must be completely freed from 
lime. 

Lomas's Process. — This process consists in tanning 
with valonia, American pearlash, and oak-bark. For 
ordinary hides and skins four baths are used. The first 
bath is composed of a solution of valonia marking about 
1° on Twaddell's hydrometer, and about 4 lbs. of 
American pearlash in 160 gallons of the solution. In this 
bath the hides remain about three days. The second bath 
is composed of valonia solution marking 3° Tw., and of 
pearlash in the proportion of 5 lbs. to 150 gallons. The 
hides remain in this bath four days. The third bath is 
composed of valonia solution at 7° Tw., and pearlash in 
the proportion of 5J lbs. to 150 gallons, in which the 
hides are immersed for seven days. The fourth or final 
bath is composed of solution at 2° Tw., and pearlash 2| 
lbs. to 150 gallons. Between each hide or skin, as they 
are placed in the bath, about 6 lbs. of oak-bark or valonia 
are spread, and in this bath they remain fourteen days. 
For very thick hides the first two baths are the same as 
for ordinary hides ; they are afterwards placed in a bath 
composed of valonia solution at 9° Tw., and 2 \ lbs. of 
pearlash to 150 gallons of solution, in which they remain 
nine days. They are afterwards placed in a final bath, 
similar to that used for the other hides, for fourteen days. 
Instead of valonia, oak-bark or other equivalent tanning 
material may be used. The hides are handled in all but 
the last bath. 

Michel, Xollen, and Hertzog's Process. — The object 
of this process is to ensure rapid tanning, by which calf 
skins may be tanned in a few hours, and cow or ox hides 
in about forty-eight, while at the same time the leather 
produced possesses all the flexibility and firmness indis- 
pensable to a perfect product. 

To carry out the invention a set of apparatus is employed, 
the essential objects of which are, first, to regulate at will 
during the operation of tanning the temperature of the 
liquors in the operating tank and in the receptacle con- 



TANNING PROCESSES. 177 

taming the hides to be tanned ; second, to regulate the 
density of the liquors in the said receptacle and also to 
change their nature as required for consecutive processes 
without interrupting the operation of the apparatus ; third, 
the clarifying of the liquors used in former processes, in 
order to enable them to serve for future purposes ; and it 
is by the combination of these means that, according to the 
present invention, rapid tanning may be effected. For 
these purposes the skins or hides are introduced into a 
drum revolving on horizontal trunnions, one of which is 
hollow, to admit of the passage of a suction-pipe leading 
from a pwmp, and a delivery-pipe leading from a raised 
liquor tank, both of which pipes descend in the drum 
within a partition thereof, so as to draw the liquor there- 
from and discharge it into the same at or near its lowest 
point. From the pump a delivery-pipe passes up into 
the tank, so that by the pump the liquor can be with- 
drawn from the drum while this continues to revolve, and 
can be discharged into the tank, it being made to pass 
through a refrigerating apparatus on its way, while from 
the tank the same liquor may either be discharged back 
into the drum, after having been raised to any desired 
temperature by means of a worm heated by steam or hot 
water, or the liquor may be passed from the tank through 
the pipes into one or more niters in order to be clarified, 
the discharged clarified liquor being collected in other 
tanks, whence it can be drawn by the pump and discharged 
into the first-named tank again. 

By these means, it will be seen that while the skins or 
hides are being continuously subjected to the action of the 
rotating drum, the liquor may at the same time be continu- 
ously made to circulate from the drum through the pump, 
refrigerator, and main tank back to the drum, whereby a 
constant definite temperature of the liquor may be main- 
tained during the tanning operation, the action of the 
refrigerator and of the heating-worm in the tank being 
regulated to any required degree. Or during the operation 
the liquor may be continuously, or periodically, clarified 
by causing it to pass from the main tank to the filters 

N 



178 LEATHER MANUFACTURE. 

and thence back to the pump, as described. Or again, 
where the hides have to be subjected consecutively to a 
series of different operations, requiring different descrip- 
tions of liquors, these may also be all effected in one 
and the same drum by withdrawing the liquors there- 
from by the pump at the end of each particular opera- 
tion, and supplying the liquor required for the next 
operation from other tanks, which also communicate with 
the pump by pipes. The delivery-pipe of the pump also 
has a branch provided with a stopcock leading to a dis- 
charge drain, so that any particular liquor that has been 
employed in the drum and that is of no further use, can 
be withdrawn by the pump and discharged to waste, 
instead of being conveyed, into the main tank again. 

The apparatus is thus described : — " Fig. 24 is a longi- 
tudinal section, partly in elevation, and Fig. 25 is a plan. 
A is a wooden drum mounted to revolve on a horizontal 
axis, having at each side trunnions that work in suitable 
bearings. On the one trunnion is fixed a worm wheel, A 1 , 
gearing with a worm driven by any suitable motor, causing 
the drum a to revolve slowly — that is to say, to make from 
ten to fifteen revolutions per minute, according to the 
nature of the hides operated on. The other trunnion is 
tubular, and through it pass freely two pipes, a and b, 
which are supported by an external bracket. The one 
pipe, a, bends downwards within the drum nearly to its 
inner periphery. A partition, p, having perforations 
through it, separates the body of the drum from the end 
space which the pipes a and b enter. A manhole, d, 
which can be tightly closed by a cover, serves to admit 
into the drum the hides to be operated on and to remove 
them. The drum has inwardly projecting ribs or studs, 
a 2 , which assist in agitating the hides as the drum revolves. 
b is a pump having its suction communicating with the 
pipe, a, and its discharge communicating by a pipe, d, with 
the top of a service tank, e. In the course of the pipe, d, 
there is interposed a refrigerator, r, consisting of a sheaf 
of tubes within a casing supplied with cold water or brine 
that is cooled by a refrigerating apparatus, which is caused 



TANNING PROCESSES. 



179 



to circulate through it while the liquid conducted by the 
pipe, d, flows through the tubes. 

" The service tank, e, is placed at a high level on a 
platform supported by columns, so that there is free 







Kar. 24. 




Fiar. 25. 



space under it. The top of the tank has an opening, 
in which is suspended a wicker basket, e 1 , which serves 
to retain solid matters discharged along with the liquid 
from the pipe d. At the bottom of the tank, e, is 
placed a serpentine pipe, k, through which steam or hot 



180 LEATHER MANUFACTURE. 

water can be passed when required to heat the contents of 
the tank. From the bottom of the tank the pipe b, pro- 
vided with a stopcock, leads to the interior of the drum a. 
At the side of the tank is placed a thermometer, h, to 
indicate the temperature of the liquid in the tank. 1 1 are 
filters, having within them perforated removable trays 
made of copper, on which are placed filtering materials, 
such as small pebbles, o, or a mixture of charcoal and 
Spanish white, p l , to purify and clarify liquid conducted 
from the tank e to the filters j j, from which it is pumped 
back by the pump b, communicating with the tanks by a 
pipe, 11. Other tanks, k and l, are provided to contain a 
reserve of liquid and to allow of subsidence, these reserve 
tanks being connected by supply pipes with the service 
tank e, and having branch pipes, r, connected to the suction- 
pipe, n, of the pump b. The branch-pipes to and from the 
several tanks are provided with suitable stopcocks, so that 
they can be charged or emptied as required. 

"Bymeans of the apparatus arranged as above described, 
the drum A, while it revolves, can be charged to any desired 
Bxtent with tanning liquid supplied by the pipe b from the 
tank e, and whilst liquid is so supplied liquid can be with- 
drawn by the pipe a and pump b from the lower part of the 
drum, and returned to the tank e cooled, if necessary, on 
its passage through the refrigerator f, or heated, if required, 
by the serpentine k ; thus the same liquid can be continu- 
ously circulated through the revolving drum with its tem- 
perature and quantity varied as required. Moreover, by 
causing the pump b to draw from one or other of the 
reserve tanks j, k, or l, the strength and quality of the 
liquid can be varied, while still its temperature can be 
regulated as above described. It is by a suitable regulation 
of the temperature, strength, and quality of the tanning 
liquid that acts in the drum a on the skins or hides which 
are kept in movement by its rotation, with suitable varia- 
tions of these conditions at the successive stages of the 
tanning process, that we are enabled to effect rapidly and 
completely the conversion into leather of high quality. 
In order that the nature of the operation may be better 



TANNING PROCESSES. 1S1 

understood, we will, by way of example, describe its 
application to the two ordinary processes, so as to guide 
a practical tanner to its application in these and in other 
cases. 

"I. Tanning Process for Soft Leather. — For calf and 
other soft skins the drum is charged with about 560 gallons 
of tanning liquor of ordinary composition, the tanning 
extracts which it contains being selected to suit the colour 
to be given to the leather. The density of the liquor should 
be from 30° to 35° of the tanning density gauge [barko- 
meter], and its temperature 50° to 60° Fahrenheit. The 
skins to be treated with this quantity of liquor may weigh 
from 1,400 lbs. to 1,550 lbs., and these are introduced 
into the drum in their soft, hairless condition, along with 
soleine (essence of distilled turpentine), in the propor- 
tion of about 3J pints of soleine to every 220 lbs. of 
skins. The drum thus charged is caused to revolve at 
a circumferential speed of from 400 feet to 410 feet per 
minute. In consequence of the ' fermentation ' or action 
resulting, the temperature rises to 65° or 70° Fahr., at 
which it is maintained for four or five hours. It is then 
allowed to rise gradually to about 85° during a period of 
twelve to fourteen hours, at the end of which time the 
tanning is complete. 

" II. Tanning Process for Hard Leather. — The process is 
similarly conducted, but extended over a longer period, 
according to the thickness of the leather, and with liquor 
strengthened by addition of about 5 lbs. of divi divi to 
every 100 lbs. of hides treated, or equivalent addition of 
other tanning material. For cow hide, for instance, the 
duration should be about 48 hours, the final temperature 
being allowed to rise to nearly 100° Fahr. At the end of 
the tanning operation the drum is almost emptied of liquor, 
and the hides are subjected for about fifteen or twenty 
minutes to the beating action of the revolving drum, after 
which fresh and very strong tanning liquor is gradually 
introduced into the drum, which is then kept revolving 
for about two hours. This has the effect of rendering the 
leather firm. The hides when tanned, whether for hard 



1 82 LEATHER MANUFACTURE. 

or soft leather, when removed from the drum are soaked 
for several hours in a weak liquor at the temperature of 
the atmosphere. The liquors discharged from the drum 
are filtered and clarified, and restored to the required 
strength for a succeeding operation." 

Keasley's Process. — This consists in the construction 
and employment of certain apparatus, whereby the opera- 
tion of tanning hides may be more conveniently, advan- 
tageously, and effectually carried on than upon the 
ordinary jilan. It is well known to all tanners that the 
quality and weight of leather is much improved and 
increased by occasionally removing the hides or skins from 
the liquor, and exposing them for a short time to the action 
of the atmosphere. The ordinary plan of doing this is 
by pulling the hides or skins one by one out of the pit 
by manual labour, with the assistance of a hooked instru- 
ment. This operation takes considerable time, and when 
the hides are large is a very laborious occupation. 

By this invention a machine or apparatus is employed 
by which a much better result may be arrived at, and at 
the same time the operation may be shortened, the labour 
considerably diminished, and the weight of the leather 
increased. The apparatus consists of a square, rectangular, 
or other conveniently shaped frame, from which the hides 
or skins are suspended vertically in any convenient 
manner. The dimensions of the framing from which the 
hides are suspended must of course correspond with the 
size of the pit, so that the frame belonging to each pit, 
and with it the hides, may be raised or lowered at the 
discretion of the workmen. Each of these frames con- 
taining the hides is distinct and separate, and may be 
raised and lowered separately by manual labour, with the 
assistance of a windlass if required; but it is found 
advisable to connect two contiguous frames together, so 
as to make them counterbalance each other, and thus 
considerably diminish the labour of working them. A 
variety of means may be devised for carrying this idea 
into effect, but those shown in the accompanying draw- 
ings will be found fully to answer the purpose. 






TANNING PROCESSES. 



183 



Fig. 26 represents a side elevation, and Fig. 27 an end 
elevation of one plan, in which the frames a a a a, filled 




Fiff. 26. 



with hides or skins b b, are suspended from the extremi- 
ties of a vibrating beam or lever c c, by means of chains 



184 



LEATHER MANUFACTURE. 



or cords d d. The tan-pits or vats e e are shown in 
section in both these figures. The beam or lever c c is 

mounted at / in bearings 
firmly fixed in the framing, 
g g, for that purpose, and is 
worked up and down by 
means of chains or cords, h h, 
which pass round a windlass 
or barrel * i, below, and are 
fastened at either end to the 
extremities of the vibrating 
beam. On the axle of the 
windlass is mounted a 
toothed wheel j, seen by dots 
in Fig. 28, and is driven by 
a pinion k, which is fixed 
on the shaft I, and is actu- 
ated by applying power to 
the shaft by means of a 
winch or otherwise. It will 
now be understood that as 
the pinion Jc, toothed wheel/, 
and barrel or windlass i i, 
are made to revolve, that one 
end of the beam or lever c c 
will be raised and the oppo- 
site end depressed by one of 
the ropes passing over and 
the other under the barrel, 
and by this means one frame 
of hides will be lifted out of 
the tan liquor while the 
hides on the opposite one 
are totally immersed. This 
operation may be reversed 
by merely turning the winch 
in the opposite direction. The ascent and descent of the 
frames is assisted by the forked guides m m (see Fig. 27), 
which work against the vertical guide-rods n n. At 




TANNING PROCESSES. 



185 



night or at other times when it is necessary that the 
hides on both frames should be immersed, this object 
is easily effected by unhooking from the suspending 
chains d d, by means of the hook r, the frame that is 
already immersed, and then allowing the other frame to 



1=^^ 




Fiar. 28. 



descend into the liquor, which it will easily do by its own 
weight. When one of the frames is raised, it is kept 
elevated by merely placing a leathern or wooden block 
between the teeth of the toothed wheel j and pinion k, 
and thereby preventing them from revolving. This stop 



1 86 



LEATHER MANUFACTURE. 



fully answers the purpose, and is found more convenient 
than a pawl and ratchet-wheel. 

Fig. 28 represents a side elevation of another plan of 
carrying out the counterbalance principle. In this plan 




Fi<?. 29. 



the vibrating beam c c is suppressed, and the suspending 
chains d d, and the working chains h h, are united together, 
and form the chains o o, which pass over pulleys p p at the 
outer extremities of the standards g g, and down between 



TANNING PROCESSES. 187 

the two other pulleys q q, and wind the barrel or wind- 
lass i i, as in the former instance. If, however, it is 
thought more desirable, the pulleys p p and q q may be 
attached to a beam, or the ceiling above, instead of to the 
standards g g. The barrel i is furnished with a toothed 
wheel j, and is driven by a pinion Jc, precisely in the 
manner already explained in reference to Figs. 27 and 28. 

In Fig. 29 is shown a means of raising the frames con- 
taining the hides one at a time. In this case the pulleys 
are fastened as before mentioned to a beam above, the 
windlass or barrel being placed below. 

Fig. §0 represents another plan of raising the frames. 
In this instance several frames, with the hides or skins 
suspended vertically, may be raised at one time, but not 
upon the counterbalance principle. The frames with the 
hides are raised by means of a rope s sss, which passes 
over pulleys tttt, affixed to a strong beam u u u above. 
One end of the rope s s is firmly fixed to the beam, as seen 
in the drawing, and the other end is passed over the pulleys 
1 1, and round a windlass at the other extremity of the 
beam. The suspension cords of the frames are furnished 
with a pulley v v, constructed in such a manner that it may 
with facility be hooked on to, or detached from, the rope 
ss, according to whether it be required to raise the frames 
containing the skins out of the tan liquor or to allow them 
to remain immersed. It will be found most convenient to 
raise only one-half the number of frames at one time, 
leaving the remainder in the tan liquor. In order to do 
this the rope s s is brought down to every other frame, 
and the pulleys v v hooked on to the rope ; then by turning 
the windlass and causing the rope s s to become coiled 
thereon, the frames, with the hides suspended therefrom, 
will be raised out of the pits, the other frames which are 
not attached to the ropes remaining immersed. "When 
the first lot of skins have been exposed for a sufficient 
length of time to the atmosphere, the frames are lowered 
into the liquor again, where they are allowed to remain 
by unhooking the pulleys v v, which connect them to the 
rope s s, and those which were before immersed are 



LEATHER MANUFACTURE. 



N/1 




now to be raised by booking 
them in their turn by means 
of their pulleys v v on to the 
rope s s. If thought desir- 
able the counterbalance prin- 
ciple may be applied to this 
arrangement of raising and 
lowering the frames by 
merely enrplojang an addi- 
tional rope, s s, passed over 
pulleys, exactly similar to 
the one shown in the draw- 
ing. One end of this rope 
also would be firmly attached 
to the end of the beam u u, 
and the opposite end to the 
windlass or barrel ; or in- 
stead of two ropes, one only 
may be employed by having 
it of sufficient length to 
pass from the end of the 
beam over the pulleys, round 
the windlass, back again over 
similar pulleys to the end of 
the beam, so as to present a 
double rope, to one part of 
which the three frames 1, 3, 
5, would be suspended, 
while the other frames, 2, 
4, 6, would be suspended 
from the other rope. Now, 
if a double rope, s, is em- 
ployed there will be no ne- 
cessity to detach the frames 
from the ropes ; the pulleys 
v v are merely made to run 
freely on the ropes, and are 
not required to be construc- 
ted so as to hook on as before 



TANNING PROCESSES. 189 

mentioned. It will now be understood that if the counter- 
balance principle is carried out in this manner, one set of 
frames will be elevated while the others are immersed, and 




the action of 1 lowering one set will raise the other ; that is, 
when the windlass is unwinding the rope to lower one set, 
it is at the same time winding up the other rope, and 
thereby raising those frames connected with it. 



X 9Q LEATHER MANUFACTURE. 

Fig. 31 represents another plan of raising the frames. 
In this plan a travelling windlass is used, which may be 
made to travel along a railway or floor constructed on the 
top of the beam above the frames. When it is required 
to raise a frame with its skins or hides, the windlass is 
moved along the railway or floor to immediately above 
the frame ; then a rope with a hook at the end is let down 
to the frame, which is then attached thereto. The frame 
is then raised up by means of the windlass until the skins 
are drawn out of the liquid and are completely exposed to 
the atmosphere ; the frame is then suspended from a hook, 
firmly fastened to the beam, where it remains until the 
manufacturer thinks it advisable to immerse the hides or 
skins. Again having raised one frame up and suspended it 
from the hook, the attendant releases the rope belonging to 
the windlass, and proceeds along the floor or railway with 
the windlass to another frame, which he raises and sus- 
pends from its hook in the same wa) r . When it is required 
to lower the frames and their hides into the liquor, this 
must be done by means of the windlass in exactly the 
same manner. 



CHAPTER XIY. 

TANNING PR CESSES. — Continued. 

Page's Process. — Casimir Bez and Sons' Process. — Snyder's Process. — 
De Bock's Process. — Funcke's Process. — Hamer's Process. — Cox's 
Process. — Nossiter's Process. — Desmond's Process. — Burbidge's 
Process. — Kleman's Process. 

Page's Process. — 'By this process the hides and skins 
are limed in weak and strong solutions, unhaired 
"drenched" in hen manure or other suitable bate, and 
immersed and handled in colouring liquors made from 
equal parts of any suitable bark and sweet fern, cutch 
and sweet fern, or gambier and sweet fern. A mixture is 
then prepared with the following ingredients : 40 parts 
of common salt, chloride of potassium, or ammonium, 40 
parts of alum, and 13 parts of saltpetre. These ingredients 
are thoroughly mixed and dissolved in four vats half filled 
with water. The vats measure 6 feet by 4, and are num- 
bered 1, 2, 3, and 4. One-third more of the mixture is put 
in 3 and 4 than in 1 and 2 vats. After a " salt solution " 
has been thus prepared, a " tin solution " is prepared as 
follows : — To 2 gallons of the stronger salt solution are 
added 2 quarts of oil of vitriol, 2 gallons of muriate of 
tin of 140° to 150° Twaddell, 28 gallons of muriatic acid 
of 20° to 30° Baume, and 2 gallons of nitric acid of 36° 
to 40° B. The hides are tanned by being immersed in 
the four vats successively, 1 pint of the tin solution being 
first added to the solutions in vats 3 and 4, and 1 pint 
added to each of these solutions whenever a fresh lot of 
hides are put in. The colouring liquor first described 
may, if desired, be made without sweet fern, or ex- 



192 LEATHER MANUFACTURE. 

clusively from sweet fern. The tanning is said to occupy 
a very short time, and the leather produced is stated to 
be " exceedingly tough and close in fibre." 

Casimir Bez and Sons' Process.* — This invention re- 
lates to the tanning of hides by aid of a continuous flow 
or current of tan liquor. The method is as follows : the 
raw hides are suspended vertically on poles arranged 
horizontally, and resting across the tan-vats or pits, 
which are on a gentle incline to encourage the flow of 
the liquid, and this latter is made and contained in vats 
at a lower level than the tan-pits. The tanning sub- 
stances are deposited on a grating above the bottom of 
the pit in which the liquor is made, so that this pit has a 
double bottom ; in the lowest portion is a suction and 
force-pump for raising the tanning liquor (made in this 
pit by admitting water above the tanning materials) to a 
reservoir above this pit, and a little above the tanning 
pits, which are a succession of vats arranged in pairs. 
This reservoir is provided with a grating near the top to 
prevent the passage of solid matters held in suspension, 
and being filled as described the liquid overflows through 
an aperture at the top of the first pair of pits, and fills 
the next pair ; passing through an aperture at the bottom 
of the pits, it again fills the next pair, and passes through 
an aperture at the top, and so on, passing through open- 
ings alternately top and bottom, till it reaches the last 
pit. In this latter a pipe enters, and by a gentle slope 
leads the liquid back again to the vat or leach, in which 
it is made to go through the same course again, so 
establishing a constant flow of liquid of uniform strength, 
the skins being arranged vertically in each tanning-pit 
on the poles running longitudinally, so that the tanning 
liquor thoroughly washes the skins on all sides in its 
passage, and so impregnates them with the tannin. 
The reservoir containing the prepared liquid is provided 
with an internal agitator to prevent any deposit that 
might arise from being in a state of rest. When a 
double set of tan-pits, and two pits for preparing the 
liquors are employed, the same arrangement is adhered to, 



TANNING PROCESSES. x 93 

and then a double-branched pipe leads the liquor from 
each of the last rows of vats back to their respective 
leaches. 

The inventors observe : " Many systems and processes 
for tanning have been employed for replacing pit-tanning 
— which up to the present time has been the most success- 
ful, both in an industrial and economical point of view. 
For some years past it has been the custom to place hides 
in the pits not only horizontally, alternated by vegetable 
astringent matters, but also vertically, suspended across 
poles, so that the skins hang in a tanning liquid ; but 
this arrangement, whilst submitting all parts of the skin 
to the immediate action of the tannin, has nevertheless 
failed to produce the results expected. The inventors 
attribute this to the decomposition of the tan liquor by 
remaining stagnant, the essential parts of the liquor 
precipitating, so that in a short time the skins are found 
in a mere neutral mass. The inventors conceived the 
idea of submitting the skins, whilst suspended in the pits, 
in a position parallel to each other, to the action of a 
tanning liquid which continually forms a double current 
across the skins and passes naturally from one pit to 
another, reaching the upper part of one to penetrate to 
the bottom of the next pit, and so on in succession, so 
that the constituents of this tanning liquid are constantly 
agitated so as to form a homogeneous whole, diminishing 
only in its action as it becomes more distant from its 
source of production." 

Description of Drawings. — Fig. 32 is a section following 
the longitudinal axis of the pits as arranged, and as 
embodying this invention. Fig. 33 is a plan of the same, 
showing a twin or double arrangement. Fig. 34 is a detail 
on a larger scale. " The tannic liquor is made in the pits 
a a, at the head of the construction, and below the tanning- 
pits, the reason of which will be hereafter explained. The 
pits a a have double bottoms perforated with holes b, on 
which the vegetable astringent substances are placed. The 
water passing through these substances becomes impreg- 
nated with the tannin and passes under the bottom b, having 

o 



194 



LEATHER MANUFACTURE. 



acquired all the requisite qualities. A suction and force- 
pump c, whose suction-tube c l , debouches between the 




bottoms of the pits, transfers the tannic liquid to the lower 
part of the juice or liquid-pit d, the top level of which 
comes above a grating d 1 , intended to stop the solid 



TANNING PROCESSES. 



195 




Ffe. 34. 



matters held in suspension in the liquid. This liquor 
pit is furnished with an agitator gifted with two move- 
ments, an up and down penetrating 
motion and a simultaneous rotary 
one. In this mariner the liquor, 
which would become hard from rest, 
is attacked not through the whole 
mass, which would require consider- 
able force, but progressively, as fast 
as the agitator descends. Following 
the line with the pit d, are a succes- 
sion of pits more or less in number 
and dimensions fff 1 , all alike, and two and two, all 
having a fixed incline, to produce a natural flow of the 
liquid at a gentle speed, regulated as experience may prove 
requisite. 

" The pits//have their sides pierced at the top with holes, 
g, through which the liquid from the pit d reaches the first 
pit, and the liquor from the pit f 1 enters the second, and 
so on in succession till the last is reached. The pits f 1 , 
whose sides are pierced below with holes h, consequently 
receive the liquor of the pits / (which precedes them) at the 
bottom, and the same pits/ receive it at the top, the result 
being that the liquor from the reservoirs d, has a double 
flow of transfer from pit to pit, and of ascent and descent, 
in leaving the level of one to reach the bottom of the next 
successively until the last is reached. In this a pipe h is 
placed, reaching to the level of the liquid, and being gently 
sloped, the weakened liquid is returned to its source, viz., 
the pit a, and being renewed and strengthened, it is then 
forced by the pump to form a continuous current. In the 
pits// 1 // 1 , the skins to be tanned are suspended on wooden 
poles m, resting across the partitions of the pit, all the 
poles being arranged parallel with the direction of the flow 
of the liquid. The skins consequently receive the action of 
the tannic liquor all over them, which, however, becomes 
weaker as the pits are further separated from the source of 
origin of the liquor, which is then returned as described to 
acquire renewed strength. As the strongest liquors are the 



196 LEATHER MANUFACTURE. 

most dense, deposits are left at the bottoms of the pits, which 
are occasioned by the liquid resting all night ; no ill effects, 
however, result from this, the skins being hung in the pits 
with the thickest parts downwards. Where double sets of 
pits are used, the liquor is returned to the leach a by a 
bifurcating pipe k." 

After the skins have remained long enough they are 
removed from the first pit and replaced by those from the 
second, and then by the third, and so on till the last skins 
are reached ; these are then put into the first pit, and fresh 
skins placed where the last were removed from. By this 
arrangement the skins throughout the pits that had received 
the action of the tan liquor, from the top to the bottom, 
now receive it from bottom to top. 

Snyder's Process. — By this process the skins are sub- 
jected to acupuncture after unhairing, and previous to 
tanning. The skins or hides are punctured with small 
holes partly through, or are perforated with holes en- 
tirely through, either on the flesh or grain side, so as to 
admit the tannin more freely and perfectly through the 
skins. The best time for performing this operation is 
when the hide or skin is in its most relaxed state. The 
punctures may be made either with a hand instrument 
with steel points, or by passing the hide under or over a 
cylinder or flat surface covered with steel points inserted 
at proper distances, varying from 100 to 300 to the 
square inch. 

De Bock's Process. — This process consists in immersing 
the skins or hides, after they are unhaired, in a solution of 
"mimosa catechu," subjecting them to handling, then 
immersing them in dilute sulphuric acid, and finally in 
water. In treating heavy skins, after having immersed 
them in the solution of mimosa catechu and handled them, 
they are taken out of the pit and drained ; a solution of alum 
is added to the mimosa solution, as also a little vitriol, which 
are well stirred in. The patentee states that in place of 
alum a solution of sulphate of magnesia (Epsom salts) and 
mimosa catechu may be employed, but that alum makes 
the hides harder. 



TANNING PROCESSES. 197 

Funcke's Process. — 1. The unhaired skins or tides are 
passed through a solution of commercial soda, and then 
hung up until nearly dry before subjecting them to the 
tanning process. 2. The skins are immersed in a solution 
of bark or other tanning material, to which is added a 
dilute vegetable acid. By this solution the pores of the 
skins are opened or extended while being exposed to the 
action of the tannic acid. 3. The skins and hides are 
again subjected to the action of a solution similar to 
the above, with the addition of a stronger solution of 
the vegetable acid, and its action is " softened " or molli- 
fied by the addition of a solution of sugar. Finally, 
while the skins or hides are subjected to the usual hand- 
ling, they are treated with a solution of tannic acid until 
the leather is finished ; but since the tanning liquor 
used in this process is of such strength as to impart too 
deep a colour for most purposes, the colour is reduced, 
when requisite, by adding, in the last stage of the pro- 
cess, sulphuric acid and salt to the tanning liquor in 
which the skins are worked. The skins or hides are 
partially dried after each operation before being submitted 
to the next. 

Hamer's Process. — The inventor says, " I suspend the 
hides or skins within an air-tight vessel, so that the 
tanning liquor therein may come in contact with every 
part of each hide ; I exhaust the air from the tank, and 
further keep the tanning liquor in motion during the 
process, so as to prevent it separating, and so that it may 
sweep off from the hides and skins the film of spent 
liquor immediately it is formed. The apparatus I prefer 
to employ is a rectangular wooden tank capable of being 
closed air-tight with a lid ; within this tank is a frame 
somewhat shorter than the tank, and capable of moving 
to and fro endwise, this motion being given to it by a 
rod which is attached to the frame. The rod passes out 
through a stuffing-box in the end of the tank, and is there 
connected with an eccentric, or other similar instrument. 
The frame runs backwards and forwards in the tank on 
suitable guide rails, and the hides or skins are hung on 



198 LEATHER MANUFACTURE. 

laths at the other end of the frame, transversely, the length 
of the tank. As the hides move to and fro, the tanning 
liquor presses first on one side of them and then on the 
other. The tank is connected with an air-pump, and is 
exhausted during the process. Tanning liquor partially- 
used may he passed from one tank to another, and air 
may be forced into the tank which is being emptied, and 
when the tank is emptied may be forced up to a pressure 
of 5 or 6 lbs. to the square inch, so as to press out the 
liquor remaining in the hides." 

Cox's Process. — In this process a frame is used with 
tranverse bars or cords, from which the hides to be tanned 
are suspended. The bars can be moved to and fro, so that 
the hides may be made to touch or not, as desired. The 
frames can be lowered into or hoisted out of the pit by 
any overhead traveller or other convenient mechanism. 
Inclined partitions are applied to the pit, which are 
preferred to consist of parallel fillets or bars, the edges of 
which approach but do not touch each other. One of 
these is at each end of the pit, but more may be used if 
desired. When the hides are first lowered into the pit 
they do not touch each other, so that the liquor may run 
freely between them. After a time, half the bars are 
moved towards one end of the pit and half towards the 
other end, so that the hides rest on or against each 
other and against the inclined partitions, so as to exclude 
the passage of the liquor between them. The hides 
are immersed in these two ways during the process of 
tanning. 

Nossiter's Process. — This invention has for its objects, 
First, to employ frames or partitions to keep the hides 
or skins separate in the pits, and not pressed on by the 
hides and skins above. Second, pressing several hides 
or skins piled together in a press, in order to remove 
the spent liquor before again immersing them in fresh 
liquor. 

Description of the Drawings. — In tanning hides and 
skins in pits, it is usual to pile them one on the other, so 
that the lower ones are much pressed on, and the tanning 



TANNING PROCESSES. 



m 



liquor cannot pass to the two surfaces of each, skin or hide, 
as it is desirable it should do. In each figure of the 
drawings the same letters are used to refer to the same parts. 
In Fig. 35, a a is a pit of the ordinary construction, and 
in place of having the hides or skins placed on each other 
in the liquor, they are separated by means of frames b b, 
which are of wood, and each frame simply consists of a 
quadrangular frame with crossbars, there being blocks, b' ', 
to keep the frames separate, so that a skin or hide placed 




Fig. 35. 



between any two frames, b, will not press on a skin or 
hide below, nor will it be pressed on by the skins or hides 
above ; thus leaving each hide free to be acted on by the 
tanning liquor in every part of its surfaces, which will be 
found of great benefit in tanning hides and skins, and the 
process of tanning may be greatly quickened ; and although 
a pit will contain less hides or skins by these means than 
when tanning in a pit in the ordinary manner, yet more 
hides and skins may be tanned in a pit in a given time 
than heretofore. In using this part of the process, the 
workman will withdraw the hides or skins from the pit 
from time to time, and submit them to fresh liquors, 
according to his judgment, as usual. The hides or skins 



LEATHER MANUFACTURE. 



with, the frames are first placed in a pit, and the liquor is 
then run or pumped into the pit. Fig. 36 is a ground 
plan of the frame. 

The inventor states that the frames or partitions may be 
made of copper or any other material, instead of wood, 
and the hides separated by means of wire or network of 
twine, or twigs, and also by bars of any other material, 
and by any other means to which the principle of the 
invention can be applied. Although he considers it is 





a 


























"1 


l> 




















P 








• 








, 








J) 
















?> 



























Fig. 36. 

better that each hide or skin should be by itself, yet there 
may be two or more placed between each pair of frames 
or partitions, but he believes there will be proportionately 
less beneficial effect from this arrangement ; and although 
he prefers that the skins or hides, with the frames, should 
be in a horizontal position, yet the system of keeping the 
hides separate may be carried out by using frames such as 
c c, Fig. 37, and fastening or lacing the hides or skins 
thereto by lacing threads d d, as shewn, the frames e 
having blocks c, to keep them separate. Fig. 38 is a plan 
of the same. 

He next describes the second part of his invention, 
which has for its object the pressing the spent liquor out 
of hides or skins before again submitting them to tanning 
liquor, and consists of using a suitable press, between the 



TANNING PROCESSES. 



surfaces of which a number of hides or skins are piled, and 
then pressure is exerted to bring the pressing surfaces, e, 




Fig. 37. 

f, of the press to approach each other, and thus to express 
the liquor therefrom. The drawings (Figs. 39 and 40) 
show one description of press — a screw-press, where the 




Fig. 38. 



pressure is obtained by means of a screw g, acting on the 
surface e, and the other press (Figs. 41 and 42) is worked 



LEATHER MANUFACTURE. 



by means of a roller h, and cords i i, as will readily be 
traced on examining the drawings. These or other presses 




Fig. 39. 

may be employed, the invention consisting of piling a num- 
ber of skins or hides between two suitable pressing sur- 




Fig. 40. 

faces, and applying pressure thereto, so that the spent 
liquor therein may be expressed, and the skins or hides 
rendered better capable of imbibing fresh tanning liquor 
when they are again immersed in the pits. 

Desmond's Process. — In this process the inventor em- 
ploys saturated infusions of oak-bark or other tanning mate- 
rial, and when the bark is exhausted, he extracts what gallic 
acid is left by fresh water, to which liquor he adds 10 ' 00 part 
by measure of sulphuric acid. In this liquor the hides are 



TANNING PROCESSES. 



203 



immersed until the hair is easily removed. "When the 
swelling is necessary, the hides are immersed in water 
acidulated with 0*05 parts by measure of sulphuric acid, 




Fig. 41. 

for ten or twelve hours. The hides are then washed and 
fleshed, and are next immersed for a few hours in weak 



Fig. 42. 



tan liquor, the strength of which is to be renewed when it 
becomes exhausted, till the skin is perfectly tanned. 

Burbidge's Process. — The inventor treats the hides 
with the extract of oak-bark, which he says he obtains 
without loss of tannin. He regulates the use of this extract 
by the barkometer. He commences with a weak extract 
at 3°, the strength of which is increased successively by 
changing the liquor three times a week, carrying it to 20°, 
the strongest liquor being used when the tanning is near 
completion. By this process the weight of the leather is 



204 LEATHER MANUFACTURE. 

increased. While by the ordinary process it takes a year 
to tan a hide weighing 80 lbs. when green, and which only 
weighs 40 lbs. when tanned, by this process it is said a 
similar hide can be tanned in three months, and it will 
weigh 40 lbs., which demonstrates that the excess of time 
employed is injurious to the leather. The amount of oak- 
bark used in this process does not exceed that of the older 
methods, being about four or five pounds for every pound of 
leather. 

Kleman's Process. — Oak-bark, such as is used in tanning 
skins, is usually taken off while the tree is in sap. It is 
dried in order to preserve it, and it is introduced into the 
tanning-pit at the same time as the skins, together with 
the requisite quantity of water. But it will be understood 
that the tanning property as well as the chemical composi- 
tion of the bark must vary according as the drying is quick 
or slow, and the greater or lesser period of time during 
which the bark is allowed to be exposed to dampness before 
the tanning begins. In most cases the bark commences 
to undergo acetous fermentation, which is completed in the 
tanning-vats. In order to utilise the tanning principle, 
whether obtained from oak-bark or gall nuts, to the best 
advantage, M. Kleman recommends the following method 
of procedure. The bark, while still fresh, is to be reduced 
to small pieces and placed in a cask, and sufficient water 
added to cover the material. The cask is then to be her- 
metically closed, so as to prevent the action of the oxygen 
of the atmosphere. The mixture is to be left undisturbed 
for a few weeks, so that the principles soluble in water 
may become thoroughly dissolved ; after this the liquor is 
to be separated from the bark. If the liquor be now heated 
to from 113° to 115°, it will enter into vinous fermentation, 
and will then contain enough alcohol to mark 1° to 2°. If 
a skin be placed in this solution, it will become very quickly 
tanned, but will be hard and horny, owing to the concen- 
trated condition of the liquor. If, however, it be diluted 
with water, excellent results will be obtained, and skins 
tanned in it will be more supple and the grain closer than 
when tanned by the ordinary method. Moreover, by this 



TANNING PROCESSES. 2 °S 

method the same quantity of bark -will produce more tanning 
matter. It is not advisable to boil the bark in water, 
because boiling coagulates the albuminous matter, which 
induces fermentation. The inventor has assured himself, 
by experiments, that bark which has undergone vinous 
fermentation gives much better results than that which has 
been subjected to acetous fermentation. 



CHAPTER XT. 

TANNING BY PRESSURE. 

Spilstrary's Process. — Drake's Process. — Knowlys and Duesbury's Pro- 
cess. — Fryer, Watt, and Holmes's Process. — Mouren's Process. 

The readiness with which tannic acid combines with 
the unhaired skin causes its exterior surfaces to become 
almost immediately converted into leather after immersion 
in the tanning liquor, by which the absorbent power of 
the skin is considerably weakened, and the interior fibres, 
in a degree, protected from the action of the tan. To 
overcome this drawback, and to favour the chemical 
action of the tannin throughout the entire substance of 
the hide, Spilsbury devised a mechanical method, for 
which he obtained a patent in 1823, by which the tannin 
was forced, by hydrostatic pressure, through the pores of 
the skin, and thus its perfect conversion into leather was 
ensured. The process is as follows : — 

Spilsbury's Process. — The hides are unhaired and 
fleshed in the usual way, after which they are carefully 
examined, and if any holes are discovered these are 
carefully sewn up, so that the skins may be water-tight. 
Three wooden frames, of equal dimensions, are fitted to 
each other, and the edges of the frames secured together 
by screw-bolts. A skin is now laid upon one frame and 
stretched over its edges ; then the second frame is placed 
upon it, so that the edges of the two frames may pinch 
the skin all round and hold it securely ; another skin is 
then stretched over the upper surface of the second frame 
in a similar manner, and a third frame being placed over 
this, confines the second skin. The three frames are then 



TANNING BY PRESSURE. 207 

pinched together and secured tightly by the screw-bolts 
passing through ears set round their outer edges ; by this 
means the skins are fixed so as to be operated upon by the 
tanning infusion. The space thus formed is of the 
nature of a bag, and is for the reception of the tanning 
liquor, which is introduced as follows : The frames being 
set upright, a pipe connected with a cistern above con- 
veys the tanning infusion to the hollow space or bag- 
formed by the two skins. The air is allowed to escape 
by a stopcock below, which is closed when the tanning 
liquor is introduced. The stopcock connected with the 
cistern-pipe is kept open when the bag is filled to allow 
the hydrostatic pressure to force the tanning liquor 
through the pores of the skin by slow infiltration, whereby 
the tannin is brought in immediate contact with its fibres. 
The effect of the pressure shows itself by a continual 
sweating of the tanning liquor at the outer surfaces 
of the skins. "When the tanning is found to be complete, 
the upper stopcock is closed, and the lower cock opened 
to allow the liquor to run off. Finally, the frames are 
shifted, the bolts unscrewed, and the pinched edges of 
the skins cut off, after which they are dried and finished 
in the usual way. 

Drake's Process. — The above process was followed, in 
1831, by a patent by William Drake, a tanner, of Bed- 
minster. By this process the hides were in the first 
instance immersed in a weak tan liquor, and frequently 
handled in the usual manner, by which they became par- 
tially tanned before being submitted to the infiltration 
process. Two hides, as nearly as possible of the same size, 
were then placed with their grain side in contact, and the 
two edges were carefully and firmly sewn together by 
means of shoemakers' waxed thread, by which a bag cap- 
able of holding tan liquor was formed. This bag was 
then suspended by loops, sewn to its shoulder ends, upon 
pegs in such a way that it could hang within a wooden- 
barred rack, and its sides pressed together in a book form. 
The upper end of this bag was left unstitched to the extent 
of about an inch, so as to admit a funnel, through which 



208 LEATHER MANUFACTURE. 

cold tan liquor was poured until the bag was full. After 
a certain time, dependent upon the texture of the hides, 
the outer surface of the bag assumed a moist or sweaty 
condition, and drops would begin to appear at the bottom 
of the bag, which were received in a vessel placed beneath. 
The liquor thus collected was from time to time returned to 
the bag, and a constant supply of pure tan liquor also 
introduced into the funnel, so that the bags were always 
full. When the hides became hard and firm, while being 
uniformly damp from the exudation of the tan liquor, 
the temperature of the apartment, which had been kept 
well ventilated, was next heated gradually to from 70° to 
150° Fahr., and the heat was kept up until the hides 
became harder and firmer in every part. As soon as the 
hides assumed black patches in places, and the tanning 
liquor ceased to diminish in strength, the tanning was 
found to be complete. The liquor was then run off by 
cutting a few stitches at the bottom, and the edges of the 
hides were then pared, and they were dried and finished 
in the ordinary way. To prevent the wooden bars within 
the rack from disfiguring the hides, the bags were occa- 
sionally shifted a little sideways. It is stated that by this 
process hides cotdd be as perfectly tanned in ten days as 
in as many months by the ordinary methods. 

Knowlys and Duesbury's Process. — By this process 
the hides are suspended in an air-tight vessel of rather 
larger capacity than their dimensions, and for this purpose 
it is lined with hooks, upon which the hides are hung at 
regular intervals, and kept expanded by means of weights 
attached to their lower ends. In the upper portion of the 
vessel or vat is an opening with a movable cover, for the 
entrance of the workmen. In the side, near the top, is a 
tube with a stopcock and coupling screws, for connection 
with an air-pump, and in a corresponding position, on the 
opposite side, is a similar tube for the admission of air, to 
create external pressure, if required. The tanning liquid 
having been introduced until it covers the hides, the vessel 
is hermetically closed, and then exhausted of air by means 
of the air-pump. As soon as the vacuum is established, 



TANNING BY PRESSURE. 209 

the contents of the vat are kept in repose for a day and 
night, after which the tanning liquor is drawn off, and the 
apparatus allowed to remain empty for two or three hours 
to permit the admission of air. This manipulation is re- 
peated several times, or until the hides are sufficiently 
tanned. The ooze must be renewed after each exhaustion 
of the vessel, and the first liquid should be weak, but as 
the operation proceeds its strength must be gradually 
increased. This means of promoting hydrostatic pressure 
by the aid of a vacuum is stated to greatly accelerate the 
impregnation of the hides with tannin, and the process is 
said to be eligible both as regards quality of leather and 
economy of time and labour. The air being withdrawn 
from the pores of the skin, its resisting action, which pre- 
vents the rapid penetration of the ooze with the skin, is 
overcome. 

Pryer, Watt, and Holmes's Process. — The object of 
this invention is to tan skins and hides by hydraulic 
pressure, which is effected as follows : — The patentees 
say, " We employ round upright tanks, to be made air- 
tight, and sufficiently strong to bear a pressure of from 
10 to 12 lbs. to the inch, according to the time intended to 
be given in the process of tanning. These tanks are to be 
fitted internally with laths or hoops, or both, to attach 
each skin to separately at its full length ; the internal fit- 
tings of the tank to move upon centres, so that the skins, 
when once placed in the tank, will not have to be taken 
out until thoroughly tanned. The skins or hides having 
been arranged in their places, the hydraulic pump is then 
set to work, which forces the bark liquor (such as is used 
in the old process) into the tanks up to the required 
pressure. The bark liquor being now in the tanks, the 
fittings, with the skins, should be moved about four times 
a day for the first three or four days ; at the end of that 
time to be moved twice a day, and at the end of the fifth 
day once, until thoroughly tanned. The liquor is then 
to be drawn off, the skins removed and others substituted 
for them, to be treated in like manner." 

Mouren's Process. — By this method a vessel, capable of 

P 



2io LEATHER MANUFACTURE. 

withstanding the pressure it is to be subjected to, is lined 
with lead, and it is furnished with manholes in the cover, 
which are made to screw on and off. Connected with, or 
standing upon, a vat containing tanning liquid, are placed 
two pumps, one communicating with the upper part of the 
vessel, and the other opening into a channel running up 
and down the side of the vessel, and which is perforated. 
The skins are placed in the vessel between two layers of 
tan ; tanning liquid is pumped into the vessel at the upper 
part, and the entire vessel is filled ; the pump communi- 
cating with the perforated channel is then used to force in 
more tanning liquid to any required pressure, which is 
denoted by a gauge on the pipe leading into the channel. 
The skins or hides are kept under pressure for periods 
varying with their nature and the purposes to which they 
are to be applied. The operation may be performed once 
or of tener. 



CHAPTER XYI. 

QUICK TANNING. 

Quick Tatyiing. — Dr. Ure'a Views. — Dussauce's Observations. — Dietz's 
Process. — ISTeedham's Process. — Nuessly's Process. — Bell's Process. — 
Baron's Process. — Another Quick Process. — Guiot'a Process. — Danish 
Quick Process. 

Quick Tanning. — "When we consider that by the old pro- 
cesses of tanning the conversion of hides and skins into 
good leather — and it was good — frequently occupied a 
period of about a year and a half, it is not to be wondered 
at that attempts should have been made to reduce the time 
required for perfect tanning by other means than those 
ordinarily adopted. In these days, with our greatly in- 
creased population and vast export trade, if we were de- 
pendent upon the old slow processes of manufacture, and 
upon oak- bark alone, how many of the industrial popula- 
tion would be compelled to go barefoot ! 

It has often been remarked that science has done less to 
improve the tanning art than has been the case with many 
other chemical industries. This is doubtless true to a 
certain extent ; but it cannot be denied that from the 
moment the principles of the art were discovered and 
explained, commenced that great change in the modus 
operandi which has ever since been working, by slow 
degrees it is true, to develop a more speedy yet equally 
good method of tanning than that pursued up to the 
latter part of the eighteenth century. That the process 
of tanning can never be both quick and good, has been 
demonstrated by long years of experience almost beyond 
the shadow of a doubt. But that there is a mean between 



212 LEATHER MANUFACTURE. 

the very quick and the very slow methods, which has now 
been arrived at, must, we think, be admitted. 

That the conversion of gelatine into leather, or rather 
into i anno -gelatine, is not of itself a slow process is proved 
by the avidity with which that substance combines with 
tannin the moment these substances come in contact with 
each other ; but, in the case of a hide immersed in tan- 
ning liquor, when once this effect has taken place upon 
its superficial surfaces, its powers of absorption — no matter 
to what extent the pelt may have been raised or swollen — 
are materially diminished, and before the tannin can find 
its way to the interior fibres of the skin it must of 
necessity remain for a lengthened period in the tanning 
liquor. JSTow it might naturally be thought that if by any 
plan the tan liquor could be forced throughout the entire 
structure of the skin, and thus all its fibres brought in 
direct contact with the astringent principle, that the 
operation of tanning would be rendered an almost instan- 
taneous process. But is this so in fact ? "We know that 
by Spilbury's and Drake's ingenious processes the tannin 
was forced through the skins by hydrostatic pressure, until 
it eventually appeared on the external surfaces in the form 
of a perspiration ; but though this would unquestionably 
prove that the astringent matter had permeated the entire 
structure of the skin, would not the conditions under which 
the tannin was introduced keep the shin porous when the 
operation was complete ? Would even the after process of 
drying — which would naturally close the pores to some 
extent — enable the leather to acquire that hardness, firm- 
ness, and absence of porosity which slowly tanned leather is 
known to possess ? In other words, although skins tanned 
by hydrostatic pressure would shrink and become more or 
less compact and firm after drying, would not moisture 
again dilate the pores when, say, boot- soles made from such 
leather were subjected to the effect of wet ? In the 
ordinary slow process of tanning the expansion of the 
pores, beyond that which is induced by the process of 
raising, would not take place, but rather, by the weight 
of hides and tan in a well-filled pit, the pores of the skin 



QUICK TANNING. 213 

would be more likely to become closed to some extent 
ichile the skin was wet, and would become still more con- 
tracted during the after process of drying. 

We would ask, does not the process of tanning mean 
something more than the mere conversion of the gelatine 
of the hide into the chemical substance called tanno-gela- 
tine ? As Sir Humphry Davy believed to be the case, does 
not the slow absorption of vegetable extractive constitute 
an important and necessary feature in the formation of 
leather ? And if so, may not the union of gelatine, tannin, 
and vegetable extractive be naturally a slow process ? If 
this be the case, we have merely to determine how long the 
process actually takes under the most favourable conditions. 
The actual period may be far short of the time allotted to 
the process by the old tanners — as it would naturally be 
when ooze is employed instead of water with the tan 
stratified with the hides ; on the other hand, allowing 
for the advantage in speed which liquid tan must pre- 
sent, the period necessary to convert hides into perfect 
leather may naturally, under the most favoured conditions, 
be slow. 

Dr. Tire's Views. — Upon this subject Dr. Ure makes 
the following important observations, and his reasoning, 
based upon Sir Humphry Davy's expressed views on the 
one hand, and the experience of practical workmen on the 
other, clearly indicates that not only is vegetable extrac- 
tive a necessary constituent of leather, but that its union 
with the gelatine of the skin and tannin is essentially a 
slow process. " When calf-skin is slowly tanned in weak 
solutions of the bark, or of catechu, it combines with a good 
deal of extractive matter ; and though the increase of the 
weight of the skin be comparatively small, yet it has be- 
come perfectly insoluble in water, forming a soft but at the 
same time strong leather. The saturated infusions of 
astringent barks contain much less extractive matter in 
proportion to their tannin than the weak infusions ; and 
when skins are quickly tanned in the former they produce 
a worse and less durable leather than when tanned in the 
latter. In quick tanning a considerable quantity of 



214 LEATHER MANUFACTURE. 

vegetable extractive matter is thus lost to the manu- 
facturer, which might have been made to enter as a useful 
constituent into the leather. These observations show 
that there is sufficient foundation for the opinion of the 
common workmen concerning what is technically called 
feeding of leather in the slow method of tanning; and 
though the processes of this art have been unnecessarily 
protracted by defective methods of steeping and want of 
progressive infiltration of the astringent liquor through 
the skins, yet in general they appear to have arrived, in 
consequence of old experience, at a degree of perfection 
in the quality of the leather which cannot be far ex- 
ceeded by means of any theoretical suggestions which 
have been advanced." 

According to the foregoing remarks, there would 
appear to be, as we have suggested, an exact point, per- 
haps now determined, when the tanning process is known 
to be complete, without unnecessarily protracting the 
operation on the one hand, or unduly hastening it on 
the other. The tanning strength of the liquors being 
always uniform (though progressively varying in propor- 
tions of tannin), and the changes of temperature allowed 
for and calculated, might not the actual period requisite 
to produce a perfect leather be determined by a consecu- 
tive series of trials ? 

Dr. Ure further remarks, "On the first view it may 
appear surprising that in those cases of quick tanning 
where extractive matter forms a certain portion of the 
leather, the increase of weight is less than when the skin 
is combined with the pure tannin ; but the fact is easily 
accounted for, when we consider that the attraction of 
skin for tannin must be probably weakened by its union 
with extractive matter ; * and whether we suppose that 
the tannin and extractive matter enter together into 
combination with the matter of the skin, or unite with 
separate portions of it, still, in either case, the primary 

* Considering the superior affinity of tannic acid for gelatine over 
vegetable extractive, is it not the former which retards the absorption of 
the latter '( 



QUICK TANNING. 215 

attraction of the skin for tan must be to a certain extent 
diminished. In examining astringent vegetables in rela- 
tion to their power of making leather, it is necessary to 
take into account not only the quantity they may contain 
of the substance precipitable by gelatine, but likewise the 
quantity and the nature of the extractive matter ; and in 
cases of comparison, it is essential to employ infusions of 
the same degree of concentration." 

In applying any of the quick tanning processes, the 
principles indicated in the above observations must not be 
lost sight of, while the practice must be in accordance 
with ascertained facts ; otherwise the production of good 
leather may be more accidental than certain, even if it 
does not become impracticable. 

Dussauce's Observations. — As to the time necessary for 
the conversion of hides into leather, Dussauce says, " Many 
tanners maintain that there is no advantage whatever in 
keeping leather in process after the tannin and gelatine have 
united. There is much diversity of opinion upon the length 
of time necessary or advantageous to keep leather in the 
tanning liquor, but it doubtless depends very much upon 
the preparation of the hide. Tanners generally do not 
pay proper attention to the early steps, those of unhairing 
and raising. Is there any necessity that time be given 
after the tannin and gelatine have united for leather to 
consolidate and grow ? Is there any gain in weight, if 
even made more durable by the delay ? " According to 
Ure's views, and the observations of the practical work- 
men to whom he has referred, an affirmative answer must 
be given to these two questions, if by "feeding the 
leather," we are to understand giving the hides sufficient 
time to take up as much vegetable extractive as they are 
capable of doing, and which, in a sense, would be allow- 
ing the leather to grow or its weight to become increased 
by the slow process necessary for the absorption of 
vegetable extractive. 

Again, Dussauce asks, " What length of time is it 
necessary to let hides tan which are limed or sweated in 
the common method ? These are questions often asked, 



S*6 LEATHER MANUFACTURE. 

and on which the views of practical men are desired. The 
fact is, that when the tannin and gelatine are completely 
united, the process of the formation of leather is ex- 
hausted." 

If vegetable extractive were not, as it has been proved 
by Davy to be, a necessary constituent of solid leather, 
this statement of Dussauce might be fully accepted ; but 
we unhesitatingly give the preference to the views of Davy 
and TJre, because we believe that leather, properly so 
called, is a compound of gelatine, tannin, and vegetable 
extractive, and not merely tanno- gelatine. " But in the 
ordinary manufacture," Dussauce continues, " it is never 
the case that the hide has received all the tannin [and 
extractive ?] of which it is capable, and therefore the 
extension of time is followed by an increase of weight. 
If all the gelatine of the hide could be exposed at the 
same moment to the action of the tannin, the process 
would be instantaneous." True ; but the product would 
be tanno-gelatine and not leather proper. " There is no 
doubt that the improvements in this direction [quickening 
the tanning process] are feasible, and that a considerable 
time is now actually gained over the old periods of 
manufacture without any injury to the leather. But no 
improvement has yet so facilitated the quick production of 
leather that a material gain in weight may not be secured 
by a protracted stay in the vats ; while attempts of this 
kind, by the use of deleterious substances, have resulted 
in rotting the fibre of the hide. Has there ever been any 
leather tanned in two, three, or six months, by any 
patented process, which has claimed to be equal to 
English bark leather? And what gives the great superior- 
ity of this class of leather, if not the length of time it is in 
the tan ? " Undoubtedly a protracted exposure to the 
tan would give the superiority referred to, but is it not 
due to the vegetable extractive, and not the tannin, 
entering into the substance of the hide after the gelatine 
of the skin has become converted into tanno-gelatine ? 
Does not the term " feeding " the leather really mean 
allowing time for the hide to take up as much vegetable 



QUICK TANNING. 217 

extractive as it is capable of doing, whereby not only is 
its weight increased but its quality improved ? * 

"It is well known," says Dussauce, " that the oak 
tanners of Pennsylvania and Maryland are about twice as 
long in tanning leather as the hemlock tanners. May it 
not be this length of tanning which gives the general 
superiority to oak leather? It is a general complaint 
that leather tanned by quick processes is wanting in solidity 
and strength. It is porous, easily filled with water, and 
wanting in durable qualities." These observations, like 
those from the same authority previously quoted, tend 
materially to strengthen the views propounded by the 
gifted observer Davy, to whose clear and original mind 
we are indebted for so much that is valuable both to 
science and to art. 

"We have been tempted to dwell thus far upon the 
comparative advantages and disadvantages of the slow and 
quick methods of tanning, in order that the reader, bearing 
in mind the support which practice has given to theory, 
may more readily form his own judgment upon the 
merits of the various processes which will hereafter be 
submitted to his consideration. 

Dietz's Process. — The object of this invention is to 
swell the tissues and fibres of the skin previous to, and 
during the process of tanning, by the employment of 
saline liquors, whereby the skin is stated to be more 
readily affected by the tanning material ; and in using in 
connection with such saline liquors tanning liquors of 
different and increasing strength, by which the centre 
and inner parts of the skin are tanned as quickly, or 
nearly so, as the outer surfaces. The inventor makes a 
weak liquor, at 2° or 3° of the barkometer, from any 
tanning material. In this liquor he mixes salt or alum in 
the proportion of two ounces to the gallon, and combines 
the whole by well stirring. The skins are immersed in 
this liquor and handled till they are saturated and the 
fibre fully swollen. The saline substances may be dissolved 
in water alone, without any tanning material, and the 
* And -which would not he attained if tan liquor only were used. 



2i8 LEATHER MANUFACTURE. 

skins saturated with, this liquor, and after complete satura- 
tion they are passed into the tanning bath. The strength 
of the bath is to be increased from 2° to 4° every day, and 
the skins stirred and handled until they are tanned. The 
time required for tanning by this process is — 

For sheep skins 2 or 3 days. 

„ calf skins 8 days. 

„ heavy leather 30 to 40 days. 

,, sole 40 to 50 „ 

Needham's Process. — In carrying out this process a 
bath is prepared consisting o£ — 

Hempseed 1 peck. 

Hops : 1 lb. 

Sal soda (soda crystals) \ „ 



Animal brain i 



4 >> 



The whole of the above are boiled in 8 gallons of water, 
and when ready is to be diluted with 40 gallons of water. 
The hides are soaked in this solution from six to thirty- six 
hours. They are put into a tanning solution composed of — 

Catechu 12 lbs. 

Divi divi 4 ,, 

Alum 4 „ 

Salt 2 „ 

The novelty in this process consists in treating the 
hides in the above solution preparatory to immersing them 
in the tanning liquor. 

Muessly's Process. — The inventor first makes a solu- 
tion composed of — 

Pyroligneous acid (wood vinegar) 1 gallon. 

Water 3 gallons. 

Hydrochloric acid 4 ounces 

Catechu If lb. 

Alum f lb. 

The whole of these are to be well mixed together by 
stirring. To 100 gallons of the above solution he adds — 

Catechu 40 lbs. 

Alum 10 lbs. 



QUICK TANNING. 219 

The hides are to be immersed in this bath, when in 
three or four days they will be tanned. Heavy hides 
require three or four weeks. 

Bell's Process. — The hides being unhaired and prepared 
as usual, are to be immersed in tanning liquor from two 
to four days. The tanning liquor is composed of — 

Wood-ashes 1 bushel. 

Water 50 gallons. 

After settling, draw off 40 gallons ; to this is added 
40 lbs. of terra japonica, and the whole boiled until the 
latter is dissolved. When cold, the solution is ready 
for use. The inventor says that by the combination 
of the alkaline ley and tannin he is enabled to prevent 
the tanning liquors from becoming sour or decomposed, and 
he is enabled to strengthen them without accumulating 
more than is necessary, and the skins will tan in a shorter 
time and with less labour than by other processes. 

Baron's Process. — By this process the hides are pre- 
pared in the usual manner, excepting that they are soaked 
for three or four hours in river water, containing yVo 0" °f 
hydrochloric acid, to neutralise any lime present in the 
skins ; they are afterwards washed in river water. This 
treatment with the dilute acid completes the perfect swel- 
ling of the hides, and they are ready for tanning. Before 
tanning, however, the colour of the leather must be fixed, 
so as to be of the usual shade. For this purpose an 
infusion of oak- bark at 1° by the barkometer is taken, and 
to which -y^-o of madder is added. The hides are immersed 
in this bath for six hours, so that the colour may be uni- 
form. They are left to rest for an hour, then turned over 
every hour. After twenty- four hours the hides are ready 
for tanning in the following manner : Dissolve catechu in 
river water, according to the number of hides to be 
tanned. The liquor is placed in a receiver covered with 
a filter and provided with a " rubber " pipe to transfer 
the liquor to the vats. The first vat contains liquor at 1°, 
with a weak solution of alum. Into this the hides are 
placed, and are occasionally stirred during the first two 



220 LEATHER MANUFACTURE. 

hours ; afterwards they are handled every three hours. Next 
day they are placed in a vat containing liquor at 2°, and 
handled four times a day, then allowed to drain two hours. 
The strength of liquor is to be increased from day to day, 
until the hides are well tanned, when they are finished in 
the usual manner. 

Another Quick Process — To carry out this process 
air-tight copper vessels are used. When the hides are 
taken from the washing water the moisture is expelled by 
pressure ; the hides are then packed in a drum fixed so 
as to have a rotary motion, and with them the necessary 
amount of tanning material is mixed, together with suffi- 
cient water to keep the contents of the vessel moist. The 
main hole of the drum is now closed, and the air pumped 
out as completely as possible. , This being done, the stop- 
cock is closed and a piece of lead pipe is added to the 
conducting tube. This lead pipe communicates with a tank 
containing tanning liquor of proper strength. If the 
stopcock be now opened, the tanning liquor rushes rapidly 
into the drum, and when a sufficient quantity has been 
admitted the stopcock is closed and the drum rotated for 
an hour, or half an hour, according to the quantity of hides 
contained in it. After two or three hours' rest the 
rotation is again resumed, and continued until the operation 
is complete. The advantages of this process are said to be 
that the pores of the skins are opened, and the tannin is 
not so quickly converted into gallic acid. The rotary 
motion facilitates the solution of the tannic acid of the 
bark, and helps its absorption by the hides, which are 
tanned in less time than without rotary motion. The 
following table shows the time occupied in tanning with 
and without rotary motion : — 



Without rotary motion 

Calf skins from 6 to 11 days 

Horse hides 35 to 40 days 

Lighter hides 30 to 35 days 

Middling cow hides^ 40 to 45 days 

Heavy cow hides 50 to 60 days 

Ox hides, light 50 to 60 days 

Ox hides, first quality 70 to 90 days 



With rotary motion. 
. 4 to 7 days 

. 14 to 18 days 

. 12 to 16 days 

. 18 to 20 days 

. 22 to 30 days 

. 20 to 30 days 

. 35 to 40 days 



QUICK TANNING. 221 

By the above process a large percentage of bark is said 
to be saved. 

Guiot's Process. — The bides are depilated and raised as 
usual. Fifty bides are tben treated in a vat of tbe fol- 
lowing dimensions : width 3 feet, and height 4J feet. 
The proportions of materials used for fifty hides are — 

Catechu 150 lbs. 

Water 50 gala. 

Stir well until dissolved, and add 50 gallons of fresh 
water, and a solution containing 3 lbs. of lime ; mix well 
together. The hides are to be immersed in this bath for 
eight weeks. During the first two weeks they are to be 
handled once a day ; the last six weeks they are to be 
handled only once a week. Another bath is to be prepared 
by taking 25 gallons of the above liquid which has been 
used, and adding to it 25 gallons of fresh water and 6 lbs. 
of white vitriol (sulphate of zinc). These are to be mixed, 
and the hides placed in this bath for four days, with stir- 
ring every day. The hides are then removed and put into 
125 gallons of fresh water, in which they are left for three 
days, when the operation is complete, and they are finished 
as usual. 

Danish Quick Process. — The following rapid method 
of tanning, by which "dressing leather" may be tanned 
in two months, is practised in Brittany and elsewhere. 
The skins are first unhaired and fleshed as usual ; they 
are then coloured by being barley and tan dressed, like 
barleyed skins, after which they are sewn up in the form 
of bags, apertures of about ten inches in length being 
left, through which they are filled with tanning solution. 
These openings being then sewn up, the closed bags are 
forcibly beaten all over for the purpose of distributing 
their contents equally throughout. They are then deposited 
in pits containing sufficient ooze to cover them completely, 
these pits being 4^ feet deep, the same width, and 8^ to 
10^ feet long. When submerged in the pits, planks 
heavily weighted with large stones or weights are placed 
upon the skins, so as to press them down forcibly towards 



222 LEATHER MANUFACTURE. 

the bottom, to increase the penetrating power of the in- 
fusion ; and in order that they may be equally tanned on 
their different sides the planks are removed three or four 
times a week, and the bags are again thoroughly beaten 
and their position changed. 

Skins prepared in this way are supple and pliable like 
crop leather, and have a finer colour than strong leather, 
but they are thinner than those made in the ordinary way, 
owing to their not swelling up by the slow process of 
feeding, and also from the pressure from within and 
without to which they have been subjected. " It is 
possible," says Morfit, " that the improvement of this 
process, which is now the old method combined with that 
devised by Seguin, may offer many advantages. The 
external and internal pressure mutually assisting, must 
certainly promote the introduction of tannin and extractive 
into the tissue of the skin. It is, however, doubtful if 
the durability and other qualities of the product are equal 
to those of leather prepared by more tedious processes" — 
an observation which is more or less applicable to eveiy 
other process of quick tanning. 



CHAPTEE XVII. 
HARNESS LEATHER TANNING. 

Harness arid Upper Leather.— Crop Leather. 

Harness and Upper Leather. — The preparation of 
leather to be dressed for harness and boot uppers is in 
many respects different from that adopted for butt or sole 
leather ; and, as will be readily understood, it must possess 
the utmost degree of toughness and strength which it is 
possible to obtain by the most careful means, from the first 
selection of the hide to the last operation of finishing. 
Although dry salted and dry flint hides may sometimes be 
employed for dressing purposes, there can be no doubt that 
the best hides for this class of leather are the recently 
flayed hides as they come from the slaughter-house. Hides 
which have been badly flayed, branded, or pitted with 
warble marks should be rejected. The hides employed for 
harness purposes are those of cows and smaller oxen. 

Selection of Sides. — " A perfect hide for dressing pur- 
poses should be thoroughly flayed, free from warbles or 
warble marks, of a close, fine, glossy grain, without any 
scratches or brands, and well filled and level throughout. 
Now many hides may have all the first qualities, and 
may be full and plump at the back, but fall away at the 
shoulders, and nothing makes a more imperfect trace or 
rein if it is not of the same substance throughout. 1 
know it is most difficult to get hides with all the requisites 
mentioned, but the only way is for the tanner to buy as 
many as he possibly can at the proper season of the year, 



224 LEATHER MANUFACTURE. 

go to market where he gets the best selection, and go over 
the lots or piles of hides himself, feeling along the shoul- 
ders and neck, and only purchasing the lots where the 
fewest flat or thin hides are." * 

Washing and Cleansing. — The hides are thrown into a 
pit containing clean water, to remove the blood, dung, 
and dirt, in which they remain for twenty-four hours. 
They are then drawn, and the horns and tail removed, 
after which they are again steeped for twenty-four hours. 
Dried and salted hides, however, require a much longer 
soaking, and must be effectually and thoroughly cleansed 
and softened before going into the lime. Old bate liquor 
is recommended as a good soak for dried and salted hides 
and kips. In former days some of the Leeds kip tanners 
considered this old soak so valuable that they worked it 
for many months without throwing it away. The fulling 
stocks are much employed for the softening of dried kips, 
and the beating action of the stocks, alternated by soaking, 
will generally bring them to nearly the condition of fresh 
hides in the course of a week or ten days. 

Liming. — The method recommended by " an old Scotch 
Tanner " is as follows : " The hides being thoroughly 
washed and cleaned in the water pits, are drawn up and 
piled one on the top of another, hair upwards, next to 
No. 1, or the weakest lime pit. The lime liquor in the 
pit must be plunged with a plunger to raise the lime 
from the bottom, the hides thrown in, two men working 
at the hides and two men carefully laying them out and 
putting down with sticks. I allow them to lie for twenty- 
four hours in No. 1, or weakest lime pit, and draw them 
next morning, great care being taken not to scratch the 
grain of the hide with the hook. Ten hides are thrown 
aside from the top of the pack, and are put at the bottom. 
The hides are then put into No. 2 lime, which should 
be a little stronger than No. 1, spreading them out as 
was done previously. I allow them to lie in No. 2 lime 
twenty-four hours, then draw them and put them into 
No. 3 lime, changing ten hides again from the top to the 
* Scottisli Leather Trader. 



HARNESS LEATHER TANNING. 225 

bottom of the pack. No. 3 lime should be stronger than 
No. 2, and so on in succession, the last lime being the 
strongest and newest. I draw all my hides every morn- 
ing, transferring ten hides from the top to the bottom of 
the pack each time, and changing them over to a stronger 
lime till they come to the strongest lime, where they lie, 
of course draining every morning, till they are ready for 
unhairing. If after eight days or so I find the hair not 
giving way, I add a little fresh-slaked lime to the liquor 
when the hides are lying up. It is impossible to give the 
proper quantity of lime that should be used (owing to its 
variable quality). Every tanner, if he pays proper attention 
to his limes, will soon find this out and regulate the 
quantity himself. Do not allow your limes to get old or 
stale ; the value of lime is not great, and there is far 
more to be lost by the hide being kept in weak old limes 
than in casting away the old lime and making fresh 
liquors. This, I think, is one of the causes why some 
tanners never get proper weight into their leather. The 
time I give my hides is from ten to twelve days, when 
they should unhair easily ; when unhaired, I throw them 
into a pit of clean water, to remove all superfluous lime 
that may be adhering to them, when they are ready for 
fleshing," We think there can be no doubt as to the 
danger of keeping hides for any length of time in ex- 
hausted or very weak lime liquors ; and it is more than 
probable that limes to which the term " weak " is applied 
frequently contain little or no lime in an active or caustic 
state, from the fact that the lime liquors are constantly 
exposed to the action of the atmosphere, from which they 
are continually absorbing carbonic acid, converting the 
caustic into carbonate of lime, which can have no effect 
upon the hides, while the liquor not being caustic would 
naturally have the same solvent action upon the gelatine of 
the skins as water, and would therefore reduce their weight. 
Bating. — After liming, unhairing, and fleshing, the 
pelts are bated in a bate of hen manure, or, according to 
the practice of the tanner, they are treated in boric or 
lactic acid solutions, &c. 

Q 



226 LEATHER MANUFACTURE. 

Tanning. — The pelts are treated in the handlers in the 
same way as those intended for sole leather, except that 
they are not kept in the old and sour liquors for a 
lengthened period, but merely sufficiently long to " clear 
the grain," as it is termed. They are next treated in 
weak sweet liquors of progressive strength, the liquors 
being returned to the leaches to be strengthened, as usual. 
The strongest liquors in the handlers should not exceed 
from 10° to 12°. The hides are treated in the handlers 
for about a month or six weeks, being worked in a round, 
after which they are placed in pits containing stronger 
ooze and finely ground oak-bark, being worked in a 
round as before, for two or three months, after which 
they are stratified with ground oak-bark in the layers, 
and treated with a still stronger ooze. After about six 
weeks the hides are taken out, and again laid down with 
interposed layers of ground bark and strong ooze, and in 
these pits they remain for about two months, the process 
being repeated once or twice more, until the tanning is 
complete. 

1 Crop Leather. — Crop leather, now almost extinct, in- 
cluded the leather prepared from the hides of cows and 
small oxen, the former (provided the cow has not calved) 
yielding the strongest and toughest leather of the two. 
As a general rule the stoutest and most compact or com- 
pressed leather (from ox hides) is used for sole leather, but 
not unfrequently leather made from crop hides was devoted 
to this purpose, without being rolled and condensed by the 
tanner, as in the case of butts. The lighter cow hides are 
used for the uppers of stout shoes and boots, inner soles, 
and also for water-boots, and other purposes. The hides 
of young oxen, being deficient in firmness and thickness, 
are chiefly used for belt leather. In the treatment of crop 
hides, they are first submitted to the usual preliminary 
operations, and are then placed in the lime pits until 
ready for unhairing, which in summer is usually in about 
eight days, and in winter from ten to fourteen days ; they 
are then sent to the beam-house, where, after unhairing, 
they are fleshed with great care, being frequently rinsed 



HARNESS LEATHER TANNING. 227 

each time, in running water if practicable, to remove the 
lime as far as possible. The hides intended for uppers 
require at least four or five rinsings, while those which 
are to be used for sole leather require but two rinsings. 
They are next raised, either by immersion in dilute sul- 
phuric or hydrochloric acid, according to the tanner's 
practice ; and they are then placed in the handlers, in 
weak ooze at first, in which they are handled daily in 
the same way as butts, and are afterwards treated in 
stronger ooze, and handled as before during a period of 
four or five weeks. They are next put into the layers, 
in which, they are carefully spread out, with alternate 
layers of finely ground oak-bark; the pit is then filled 
up with ooze. At the end of about six weeks they are 
taken out and subjected to a fresh change of bark and 
ooze, this being repeated once or twice more until the hides 
are perfectly tanned. 



CHAPTER XVIII. 

AMERICAN TANNING. 

Cold Sweating of Hides. — Sweat Pits. — Treatment of Hides in the Sweat- 
pits. — Treatment of Hides after Sweating. — LimiDg. — Unhairing by 
Prof. Lupkin's Process. — Beam Work. — Trimming or Kounding. — 
Grinding the Bark. — Leaching. — The " Press" Leach. — Eaising with 
Vitriol. — Handling. — The Eocker Handler. — The Layers. 

While our American cousins freely and generously 
acknowledge the excellence of English tanned leather, 
and highly compliment our manufacturers upon the care 
and economy with which they conduct their various 
operations, there is much in the Transatlantic system of 
tanning which deserves and must command attention. 
If, however, our great American competitors were as 
silent upon the subject of which we are treating as are 
our own countrymen — with few exceptions — we should 
have but little to communicate as to the modus operandi 
adopted in the United States. The whole fraternity of 
tanners, however, both at home and abroad, are indebted 
to Mr. Jackson S. Schultz, an eminent American tanner, 
for a very clear and practical book on the manufacture 
of leather* as conducted in the States, being the substance 
of a long series of valuable papers contributed by him to 
the Boston Shoe and Leather Reporter. Independent of 
the great service which these writings must have rendered 
his own countrymen, there is a great deal of information 
conveyed by the pen of this astute writer which should 
be read by all who follow the art of tanning, even though 
they treat specially of the method adopted in the United 
States. 

* " Leather Manufacture." By Jackson S. Schultz. 



AMERICAN TANNING. 229 

"We now purpose giving, as briefly as possible, a risumi 
of the American system of tanning, as explained by Mr. 
Schultz, but must refer the reader to his own admirable 
work for more complete information. 

Cold Sweating of Hides. — While in Great Britain 
sheep skins are freed from their wool by " steam sweat," 
as it is called, in the United States a system of cold 
sweating is adopted for heavy hides which at present 
is chiefly confined to that country. Schultz says, "It is 
now demonstrated that a wooden, brick, or stone structure, 
on the top of the ground, can be so completely protected 
from the rays of the sun and other atmospheric influences 
as to malce a good sweat-pit. The ice companies have 
adopted surface structures of wood filled in with sawdust, 
tan-bark, or charcoal between the outside clapboards and 
the inner linings of their buildings, and this same form 
of structure will make a most serviceable tanner's sweat- 
pit. But since the sweat-pit is subject to greater changes 
of atmosphere than the ice-house, it is desirable that the 
inner lining of the sweat-pit should be of a more endur- 
ing substance than wood. The damp but warm atmo- 
sphere of tanners' sweat decomposes the fibres of the 
wood very fast. On account of this liability to decay, if 
for no other reason, the sweat-pits of the tanners should 
be constructed of stone or brick. 

Sweat Pits. — " The structures may be wholly above 
ground, and should be so placed that a wheelbarrow may 
be run from the floor of the beam house to the main passage- 
way of the sweat-pit. These passages should be wide — not 
less than 6 to 8 feet — and be so thoroughly lighted both 
from top and ends as to make their passage by workmen 
and employes both easy and agreeable. The height of this 
main passage-way should extend above the surrounding 
pits, and by this ' lantern ' construction both light and 
air can be secured in the passage-way below. The pits 
themselves should extend from both sides of this main 
passage, and be connected with folding doors wide enough, 
when fully open, to admit a wheelbarrow." 

Each of such pits must be large enough to hold one 



230 LEATHER MANUFACTURE. 

pack of hides, and high enough to allow the suspension 
of a side doubled, with 2 feet clear above and 1 foot 
below the hooks. The pits should be about 8 feet wide, 
giving space for two tiers of sides and gangway for the 
workmen. The pits should be so constructed that light 
may enter sufficient to allow a close examination of the 
hides without the employment of a lamp, and should be 
kept in such a cleanly condition that any person could 
enter the pit without soiling his clothes. Mr. Schultz 
lays great stress on this point. The temperature of the 
pits is kept under control by steam and cold water, which 
are admitted through the main passage by means of 
pipes. " A properly constructed pit should have a false 
bottom, under which the steam may be forced, to find its 
way, in condensed spray, up through the suspended sides. 
This process will adequately warm the pit. When too 
warm, cold-water maybe thrown from the mouth of a 
sprinkler over the whole surface, and thus, in a few 
moments, cool the whole space, and leave a desirably 
moist atmosphere." The temperature should be main- 
tained at from 60° to 70°, with globules of moisture rest- 
ing on all parts of the suspended hides, which eventually 
collect and drop from points of the hair. 

The sweat-pits are covered by stout timber, above 
which is a layer of earth about 2 feet thick, which is kept 
well watered, so as to protect the interior from the heat 
of the sun's rays. The sides of the pits may be protected 
with the same object, either by means of earth or spent 
tan. "With pits so constructed hides may be properly 
"sweated" in from three to seven days — usually about 
four or five if the hides are in proper condition. The 
cold sweating process is, however, chiefly adopted for dry 
"flint hides." Before submitting the dry hides to the 
sweating process, they require to be softened or brought 
to the condition of green hides by the usual methods of 
soaking, beating, &c. 

Treatment of the Hides in the Sweat-pits. — The 
hides should be hung on the racks by tenter-hooks, being 
suspended either from the shoulder or from the butt, but 



AMERICAN TANNING. 231 

whichever method is adopted the same should be applied 
to all, so as to ensure uniformity of action in the sweat- 
pits. Since the sweating is more rapid above than below, 
and as the thicker parts of the hide will resist the action 
of the sweating longer than the thinner parts, it would be 
better if the pates and butts could be suspended higher 
than the bellies and shoulders ; but since this would in- 
volve considerable difficulty, the same result is attained by 
changing the position of the hides after three or four days, 
when the process of sweating will have advanced con- 
siderably. This operation of "assorting out," as it is 
termed, requires great care on the part of the workmen, 
since up'on this in a great measure depends the success of 
the operation. This care is specially necessary at this 
stage, since no two hides, however uniform in character, 
will sweat exactly alike. " ISTo hour in the whole day," 
says Mr. Schultz, "should be without a visit to the 
advanced sweats. When a few sides give indication of 
' coming ' prematurely, before their proper time, the3 r 
should be dropped to the bottom of the pit, and allowed 
to lay in piles until their less advanced companions catch 
up in the process of decomposition." 

Treatment of Hides after Sweating. — The sweated 
hides are next thrown into the mill for a few moments, to 
wash away the dirt and " slime," and to rub as much of 
the hair off as can be removed by such means. In respect 
of this operation, however, Mr. Schultz says : " During 
this short and damaging process two things happen — 

1. The loose hair is fulled into the flesh so firmly as to 
make it difficult to remove afterwards on the beam ; and 

2. To pound out much of the gelatine of the hide, which 
at this period is almost in a soluble condition, and will 
part from its proper lodgment in the fibre almost as freely 
as the slime and dirt with which the surfaces are supposed 
to abound. Indeed, much of the substance that is regarded 
as ' slime ' and ' dirt ' is the gelatine, which, when com- 
bined with tannin, goes to make leather." He very 
properly condemns the practice of fulling or milling 
the hides after sweating, which must reduce their weight 



232 LEATHER MANUFACTURE. 

considerably, besides disturbing the delicate structure of 
the hide itself. The system which many intelligent 
tanners of the States have found most practical is to 
throw the hides as they are removed from the sweat-pits 
into weak lime liquor for a short time, by which a slight 
plumping or swelling of the hides takes place, and the 
slimy condition disappears, while the hair does not attach 
itself to the flesh as in the former treatment. He advo- 
cates part liming and part sweating as a good method of 
loosening the hair. 

" There can be no doubt," he says, " that our American 
system of cold sweating is calculated, beyond any other 
known method, to make a firm, compact fibre when 
properly used, and besides it is specially adapted to the 
preparation of the dry hides of our continent. It only 
remains for me to say a word on the subject of ' grease ' 
and ' salt,' as among the hindrances which affect and 
control the sweating of hides. All sweat tanners fully 
understand that the salt (if the hide is salted or pickled) 
must be fully soaked out before the hide will sweat. 
From this, among other circumstances, is deduced the 
inference that this process is a decomposing one, for, 
so long as the hide is held (cured), from the presence of 
salt, carbolic acid, and other tanning ingredients, the 
sweats will not operate on the hide. So, too, if this is 
covered with grease, as many of our Western and Cali- 
fornian hides are, it will not sweat evenly, owing to the 
presence of the grease on some portions more than others." 

Liming — The method of preparing the lime liquors in 
America is in many respects different from that generally 
adopted in this country, one point of difference being that 
less lime is employed than is usual here. After recom- 
mending that the lime should be kej)t in dry and confined 
apartments, where neither moisture nor air can reach it, 
Schultz recommends that a half hogshead should be 
placed near the lime- vat which has to be replenished. For 
a pack of 120 to 140 hides about a bushel of lime is put 
into the tub, and one or two pails of water poured on ; the 
vessel is then to be covered with thick canvas. As the 



AMERICAN TANNING. 233 

water is absorbed more is added if required, but our own 
experience in the slaking of lime teaches us that a much 
less quantity than two pails of water would be sufficient 
to slaken a bushel of lime. It is always a great advantage 
to cover up the vessel in which lime is slaked, since by so 
doing much less water may be used, and the confined 
steam aids the slaking greatly. 

"Whereas in this country it is usual to put a considerable 
quantity of lime in the pits, Mr. Schultz says, " Nothing 
but pure limewater should ever be allowed to enter the vat. 
This will not only render frequent ' cleaning out ' unne- 
cessary, but will save the flesher's edge, and also save time 
in many'respects." He allows three or four days only for 
the liming, and in this time " the lime will not improperly 
fill the hide, and when unhaired it may be speedily reduced 
to a proper condition. The reduction (depilation) will be 
well begun by throwing the hides or sides into a wheel 
(drum), and with a flow of warm water turned on run them 
for ten minutes. The advantage of warm instead of cold 
water is very marked, and may at this stage of the process 
be freely used with safety. It is always safe to use on 
hides filled with lime heat to the extent of 110°. . . This 
rinsing process will remove the greater portion of the 
lime, and will ordinarily prepare the hides for the liquor." 
Some tanners, however, to get rid of the lime more effec- 
tually, use hens' dung or sour bran liquor. This latter 
precaution, however, is not considered necessary for sole 
leather, while for upper leather, it is necessary that the 
skins should be as free as possible from lime before they 
go into the handlers. The sour liquors of the handlers 
are deemed sufficiently active to remove the lime from 
heavy hides, provided the fibre has not been unduly 
strained in the beam house. 

Unhairing by Prof. Lupkin's Process. — By this method 
one tanner in New Jersey prepared not less than 50,000 
hides annually with great success. His packs were made 
up of about 50 hides each, either cured, green, salted, or 
dry Buenos Ayres or Hio Grande. The green weighed 
about 50 lbs. and the dry about 20 lbs. For such a pack 



234 LEATHER MANUFACTURE. 

80 lbs. of lime would be slaked, but the lime was not watered 
after slaking, as usual, but was left in the condition of a 
thick paste. A small portion of this was kneaded thoroughly 
with 10 lbs. each of soda ash and powdered sulphur. When 
these substances were well mixed, they were thrown into 
the tub in which the bulk of the lime reposed, and while 
this was still warm ; the whole were then thoroughly 
mixed, and the tub then filled with lime liquor and the 
whole well stirred. When this was done, the mixture was 
poured into the vat, and the whole thoroughly plunged. 
No more liquor was employed than would be sufficient to 
cover the 100 hides when thrown in. The lime was kept 
up to summer heat by the application of steam. The 
handling was performed once or twice a day, if thrown 
into the vat as usual. Mr. Schultz says, " There is no 
doubt that it is a good method of unhairing for any 
hides or skins, and when a soft and smooth grain is 
desirable it is a valuable improvement. Of course, it 
is slightly more expensive than pure lime, and, for this 
reason, has not found general favour/' The soda ash in 
this process combines with a portion of the lime, forming 
caustic soda. 

By another process the hides, after the usual preparation, 
are thrown into a strong lime for 8 or 10 hours, when they 
are taken o at and immersed in water up to 1 1 1°. The warm 
water soaks, softens, and swells the roots of the hair, and 
has much the effect of the " scalding " applied to hogs. 
" So little lime permeates the inner fibre, that, after a slight 
wheeling, the hides may be thrown into cold water and 
allowed to cool and plump preparatory to taking their place 
in the handlers. The process is strongly commended for 
sole leather, particularly where great firmness of fibre is 
desired. The tanner who tries this method must be satisfied 
if he gets twenty to thirty sides per man, unhaired and 
fully completed for the liquor, per day." Instead of the 
usual handling in the lime, the hides may be " strung " 
together, and reeled over from one pit to another by means 
of the hand-reel, Fig. 43. This simple contrivance for 
removing hides from one pit to another, as a substitute 



AMERICAN TANNING. 



235 



for the usual handling, should command attention. In 
speaking of its capabilities Schultz says, "The facility 
with which packs may be thus transferred from one pit 
to another commends this skeleton reel to all tanners. It 
is safe to estimate the performance of this machine with 
two men as equal to that of six men by the old process. 
Besides, it does not require either man to stoop to his 
work, and the labour is therefore easier. The stand and 




Fig. 43. 

skeleton drum should be made of as light material as 
possible, so that its transfer from one vat to another may 
be effected by two men with ease. As there need be but 
one of these reels in an ordinary sized tannery, the tanner 
can well afford to have the frame, drum, and bearings 
made of substantial but light materials, well adjusted in 
all parts, even with brass bearings. Two men can shift 
10,000 in ten hours. The hides may be tied together with 
strings.'' 

Beam Work — "No amount of labour andcare," says Mr. 
Schultz, " in the after processes can atone for neglect in 
this department. The flesh should all be removed, and the 



236 LEATHER MANUFACTURE. 

natural structure of the hide (pelt) should not be disturbed 
or even touched with the edge of the flesher.*. . . The 
usual flesher and half-round beam are too familiar to the 
tanner to require notice in this connection, but within a few 
years the French and German beam-knife has been intro- 
duced, and received with general favour. This knife is about 
one-third larger than ours, and is not more than two inches 
wide ; the material is the best steel, and is not more than 
a quarter of an inch in thickness in the rib or centre. The 
blade is so supple that the handles can almost be brought 
together. It is claimed for this knife that by its supple 
nature it bends around the rounded convex form of the 
beam, and makes a flatter cut on the flesh of the side, less 
concave than a stiff, straight-edged flesher cutting on an 
oval or convex surface. To this extent the new knife cer- 
tainly does present advantages, and may be safely trusted 
to do good work in skilled hands." 

Trimming or Rounding. — This author speaks highly 
of the economy and judgment displayed by the English 
tanners in their method of rounding, and gives the following 
reasons why this method is adopted : — 1st. The shoulders 
and offal are much thinner than the butts, and, therefore, 
tan in a shorter time. 2nd. The offal being used where a 
tough fibre is required, slack, or at most a full tanning, 
is all that is required. 3rd. The boot and shoe manu- 
facturers, not only of Europe but of America, have so 
classified their work that those who use butt leather 
largely do not require so much " inner soleing " and 
"welting" as would come from the bellies and shoulders 
of these out-soles. 

Mr. Schultz says, " It is probably true that the population 
of Great Britain is better and more economically shod than 
any other people in the world. A portion of the economy 
is due, however, to iron rather than leather, f Much of the 
economy here conceded arises from their method of tritn- 

* Fleshing-knifs. 

t This remark is specially applicable to the present time, when metal 
sole and heel "protectors" are so extensively applied by the public 
themselves. 



AMERICAN TANNING. 237 

ming and rounding their hides and skins. That which 
belongs to the glue-maker never goes beyond the beam 
house in any tannery in Europe." 

Grinding the Bark — In the United States the spent 
tan is largely used as fuel by the tanner for the generation 
of steam for his grinding-mills, for the leaching of bark, 
and other purposes, and to a great extent has supplanted 
the use of all other fuel, and even water-power. " So 
absolutely inexpensive is this substitute," says Mr. Schultz, 
" that power and heat may be used without stint and limit 
in the manipulations of all our modern sole leather 
tanneries. . . . The fact, then, stands conceded that the 
wet spent tan from an ordinary sole leather tannery will 
give ample power to grind all the bark and heat all 
the liquors required." He writes strongly against mills 
which grind at high speed, and doubts whether a motion 
over 80 revolutions per minute is either profitable or 
effective. The benefits which may be derived by adopting 
a higher speed in nowise overbalance the defects in 
grinding and danger of fire from excessive friction. " A 
quick motion has the effect to ' throw up ' and ' back ' the 
bark, rather than take it in and pass it through the grind- 
ing surfaces, as a slower motion will." He recommends 80 
revolutions on a small and 70 revolutions on a large mill 
as the proper motion. 

Speaking of the American methods of grinding and 
leaching, Schultz says it is estimated that from 7 to 10 
per cent, of tannin is left in the bark, and it is doubtful 
if any of their methods will take out the remainder profit- 
ably. He says, moreover, that " the time may come when 
hemlock and oak-bark (the chief materials used in the 
States) will be so scarce and dear as to necessitate other 
means than grinding and leaching for extracting all the 
strength from the bark." It seems strange that when our 
American cousins are so ingeniously utilising what they 
consider their " waste " tan, that they are wasting* in a 
true sense from 7 to 10 per cent, of material. 

* Chemists are now employed in all large American tanneries, and all 
mateiials much more thoroughly extracted under their direction. — Ed. 
Fifth Edition. 



238 LEATHER MANUFACTURE. 

Leaching. — " The full and perfect extraction of all the 
tannin from the bark is not only desirable, but it is of 
primary importance ; it is equally essential, however, that 
this subtle elixir should be extracted without deterioration 
or injury. It is found in practice not at all difficult to 
wash out all the extractive or soluble matter from the 
bark ; but to separate and take out the greatest amount of 
tannin, leaving the largest portion of colouring and 
resinous matter behind, is quite a different matter, and 
one which has taxed the efforts of our best tanners. The 
system of leaching which will enable the tanner to control 
and separate these qualities is, in my judgment, the 
system to be most commended." In this view Mr. Schultz 
does not appear to be supported by some of the largest 
American tanners, as he frankly admits, but he believes 
that their theory is based on the assumption that colouring 
matter, entering into the substance of the hide, gives 
weight ; and that also the resinous matter in some myste- 
rious way attaches itself to the leather, defying the action 
of the scrubber to wash it off. To this theory he strongly 
objects, and asserts that " tannin, and not colouring or 
resinous matter, enters the fibre and gives weight." But if 
Davy's well-known theory be accepted, does not the colour- 
ing matter (setting aside the resinous matter) enter into the 
substance of the hide with the vegetable extractive, which 
forms an essential ingredient in the formation of leather ? 

The system of leaching in America, by the application 
of heat, appears to be open to objectioD, since the chief 
tanning agent, hemlock-bark, yields not only an objection- 
able colour, which is more freely extracted in hot than in 
cooler liquors, but also resinous matter, which can play no 
useful part in tanning. " The union-crop leather tanners," 
Mr. Schultz remarks, " have learned to appreciate the value 
of moderate instead of extreme heat, and when better 
methods of grinding and screening the bark shall be appre- 
ciated at their full value, then I assume that even less heat 
than at present will be employed by them, and the more 
nearly summer-heat (60°*) is adhered to, in the head leach, 
* The summer-heat in this country is 78° Fahr. 



AMERICAN TANNING. 239 

the more modified and controllable will be tbe colour." 
Since it is so well known that tannin is freely soluble in 
cold water, and that colouring matter is more readily 
extracted from bark by hot than by cold water, it must 
certainly be erroneous, especially if the colouring matter 
is of an objectionable character, to use heat for the leaching 
of this otherwise most useful bark, hemlock. Mr. James 
Cleaver, an American tanner of repute, proved that he could 
make from 190 to 200 lbs. of leather with one ton of bark, 
never employing a higher temperature for his head leach 
than that of summer-heat, except in winter. 

Of the several systems of leaching adopted in America, 
we may select the following : — 

The " Press " Leach. — The number of leaches in a set 
(or round) should correspond with the number of days in 
the week. By this method one new leach is filled in each 
round every day in the week, but if more than one leach 
is required for the day's work, then the sets of leaches 
should be multiplied rather than disturb the order of the 
round. This arrangement gives at least five days for the 
leaching of all the bark, which is fully time enough. It 
is strongly recommended not to break the round, which 
only leads to confusion and waste. As to when and where 
heat may be applied, Schultz says, " Under no circum- 
stances is heat to be applied to any other than the back or 
weakest leach. This will bring the strong liquor of the 
set on the head leach comparatively cold, or at most 
summer-heat. This course will take all the liquors in the 
yard in a proper condition to go upon the leather without 
coolers or waiting. It will leave behind much of the 
colouring and resinous matter, and send forward a pure 
tan liquor free from all sediment and impurities." 

The principle on which the "press leach " works is thus 
described: "Warm water or liquor is more expanded, 
and consequently lighter than cold. Strong liquor is 
heavier than weak. Now if we put the two light condi- 
tions together, viz., hot and weak, and place them on top 
of the heavy and cold liquor, they will remain separate 
for all the time, or so long as these conditions are main- 



240 LEATHER MANUFACTURE. 

tained. A simple experiment with water and tan liquor 
in a tumbler will demonstrate this practical result. Weak 
tan liquor will stand all day on the top of strong and 
heavy liquor, if not agitated. Now if to the weak liquor 
we add heat, the separation will be still more marked. A 
tumbler half filled with weak and warm liquor may be 
forced out of the top by gently inserting strong and cold 
liquor underneath by means of a pipe. The action of 
these bodies, if the experiment is carefully made, will 
satisfy any one that the system of press leaching can be 
carried on without mixing the liquors on their passage, if 
the system recommended be followed." In other words, 
it is a question of gravity ; the heavier liquid, or that 
which is richest in tannin, will form the lower stratum, 
and the weak the upper stratum ; and if strong cold 
liquor were introduced from above, through a funnel con- 
nected to a long tube, the end of which reached to the 
bottom of the vat, the weaker liquor would gradually rise 
to the surface. 

In working the press leaches, each of the six leaches 
is filled at all times from two-thirds to three-fourths 
with bark, and stands covered with liquor varying in 
strength with the strength of bark in each. " Let us sup- 
pose," says Schultz, "that the head leach has just been filled 
with fresh- ground tan ; the last or back leach is filled with 
spent tan ready to pitch, and the intermediate four leaches 
are divided into both, as to strength of liquor and age of 
bark, from these two points. No liquor is sent into the 
yard except from the top of the head leach, and where 
very strong liquors are needed, only one liquor is so sent 
from each head leach, so that the accumulated strength of 
all the bark in one leach is concentrated in this one liquor. 
If a less degree of strength is required, then two runs 
may be taken off, and in exceptional cases, even three or 
four. The liquor thus sent into the yard is not returned 
until the strength is taken from it, and it is either sent off 
into the stream as worthless, or sent back to the back 
leach, after passing through the heater, and heated up to 
100° or 120°. I shall insist that the spent tan liquor, 



AMERICAN TANNING. 241 

which is accumulated acid (gallic), shall go back for sole 
leather, and shall go off into the stream if light leather, 
such as calf, kip, or even harness, is to be tanned." 

The usual practice in working the leaches is to run the 
strongest and newest liquor direct from the leaches upon 
the head packs on the last layer. These liquors should 
stand at fully 30° by barkometer. After thirty days' use 
they will be reduced to 24°, a portion of which indicated 
strength will be " acid." Twenty days' further use on the 
third layer will reduce the strength to 18°, and so on until 
the liquors will be nearly exhausted and contain little else 
than acid.. These liquors are put on the first layers, or 
run into the handlers to be more fully exhausted. The 
liquors are run from the leaches by covered and enclosed 
wooden tubes or bored- out logs. Mr. Schultz speaks 
strongly against the practice, even if accidental, of allowing 
warm liquors to come in contact with half- tanned or green 
hides which have been sweated, especially in warm 
weather, as decomposition and injury are sure to result. 

Raising with Vitriol — The practice of the American 
tanners with regard to the employment of sulphuric acid 
(oil of vitriol) for raising the pelt is variable. While 
some pass the sides through the handlers before introducing 
them into the acid liquor, others use the acid first and 
colour them afterwards ; other tanners, again, add the acid 
to their handler liquors, by which they plump and colour 
the pelts at the same time, and when this method is 
adopted the strength of the liquor is renewed with sweet 
highly coloured liquor as each new pack is treated. 
Regarding the employment of sulphuric acid for this 
purpose, Mr. Schultz observes, " Yitriol- raised leather, 
when treated in the after process in weak liquors, produces 
a most unsatisfactory result. The grain is poor, the fibre 
coarse and ' hatty.' I do not here attempt to solve the 
mooted question whether vitriol does not destroy the 
tannin. It is conceded that it will plump and hold the 
fibre and will facilitate the tanning, but whether these 
advantages in an economical point of view are not more 
than counterbalanced by its destructive action on both 



242 LEATHER MANUFACTURE. 

fibre and the tannin I shall leave for future experience to 
determine." He, however, concedes that vitriol "pre- 
serves the hides, and holds, when combined with salt, the 
gelatine from decay," and he moreover states that "all the 
green sheepskins that come from England to this country 
(America) in casks are preserved by this process, and may 
be so held without damage for years ; " but he further 
observes that unless the acid in these skins is neutralised 
before they are put into tan liquor, they swell to more 
than double their wonted thickness, and will tear as easily 
as brown paper. 

While Mr. Schultz allows that sulphuric acid raising 
may be adopted, without material damage, for hides which 
have been limed, he says, " In my judgment vitriol should 
never be used to raise purely sweat stock," in which, 
we imagine, none will differ from him ; while it is equally 
clear that lime would be an appropriate steep for sweated 
stock. 

Handling. — In America the system of handling by 
withdrawing the packs and allowing them to drain and 
then returning them to the handlers, as is usually practised 
in this country, or of working the handlers in rounds, have 
been substituted by mechanical appliances which reduce 
the labour of the workmen in this branch of the business 
to a minimum. The most generally adopted contrivances 
are the hand-reel (Fig. 43) and the " rocker." The former 
machine is placed in the alley- way between the pits to 
be shifted, and the hides to be transferred being tied 
together, are forced over from one pit to another by means 
of the revolving drum, which is turned by its handle by 
one man, while a second man adjusts the hides in the 
"head" pit. It takes only four minutes for two men to 
transfer 150 hides from one pit to another. 

The Rocker Handler is a frame set in the top of pits, 
and is made of wood. The frame fills the pit within two 
inches of each end and one inch on each side, so that 
when it rocks from the centre it will play without 
touching (Fig. 44). It should be made of two-inch timber, 
and framed two by sis inches. The end-pieces should be 



AMERICAN TANNING. 



243 



made of hard wood not liable to split, since these have to 
bear the strain of the whole pack. The centre of this 
frame rests on pivots, supported by uprights from the 
bottom of the pits. A stop at each end of the pit prevents 
the rocker from dipping more than about eight inches. 
The hides are attached alternately by the head and tail to the 
end-pieces, with backs up and bellies down, by means of 
hard wooden pins permanently fastened in the head frame- 
pieces. Usually one end is fastened directly to or over 
the pin, and the other by an adjustable string which 
need not be more than a foot long, and may be made by 
a permanent slip knot to act continuously. 




Sometimes " white spots " appear upon the surfaces of 
sweated hides after having been partially coloured in the 
handlers. These spots have been proved to be due to 
grease left by imperfect beam work, and the most approved 
remedy for this is caustic soda, a solution of which is 
rubbed over the spots, when they quickly disappear. 
This defect does not apply, of course, to limed goods. 

_ The Layers. — Eespecting the proper disposition of the 
hides in these pits, Schultz observes, " The question has 
often been raised whether the hides should be laid grain 
or flesh side up in the layers. The practice is to lay 
grain up, and this is justified on the ground that in 



244 LEATHER MANUFACTURE. 

' hooking up ' the grain is more apt to be scratched and 
marked than if laid flesh side up. If, as it seems quite 
likely, colour is seriously affected (particularly hemlock 
tannings), by the settling of the colouring matter on the 
grain, and a deeper, darker red is the result, then I think 
tanners may well inquire whether, in their attempts to 
avoid hook-marks, they do not entail upon their stock a 
worse evil. Besides, I will suggest in this connection 
whether it is not probable that tannin will enter the fibre 
of the hide more naturally from the flesh than from the 
grain surface. The pores of the hide, when on the 
animal, certainly do open their valves outwardly from the 
flesh, for all the emanations of the animal body go 
through these outward- opening valves or pores of the 
skin, and never receive back from the grain to the flesh." 
To this we may add, as a further suggestion, that while 
the tannin of the bark and ooze is being gradually 
absorbed by the hides, the liquor is kept in a continual 
state of imperceptible movement, by which the tendency 
of the exhausted liquid would always be upivard ; while 
the liquid renewed with tannin from the ground bark, 
being now heavier, would take its place, and thus a con- 
tinual upward movement would result, as in the circulation 
of sap in a tree, though not of course with the same vigour. 



CHAPTER XIX. 

HEMLOCK TANNING. 

Pratt's System of Tanning. — Hemlock Tanning of New Lebanon. — 
Hibberd's Process. 

The great success which attended the employment of 
hemlock-bark in some parts of the United States induced 
English tanners to turn their attention to this prolific 
source of tanning material, and during the past thirty 
years or so a a extract of the bark has been imported from 
Canada in large and increasing quantities. The hemlock 
spruce-fir abounds in the northern states of Pennsylvania 
and Canada, and the readiness and cheapness with which 
the bark is obtained have rendered it the chief tanning 
material of those states, and a source of considerable in- 
dustry in Canada. The extract comes over to this country 
in casks, of the consistence of treacle, and is of a dark 
brown colour. This extract is not soluble in cold water, 
owing to the large amount of resinous matter it contains, 
but it is freely dissolved in water at 150° Fahr. It may 
be employed alone, but owing to the indifferent colour it 
imparts to leather, it is generally used in combination 
with other tanning materials. According to Ramspacher, 
it yields 25 per cent, of tannin. 

Pratt's System of Tanning.— The Hon. Zadock Pratt, 
who was one of the most skilful and experienced manu- 
facturers of leather in the United States, furnished Dr. 
Morfit with some very elaborate and interesting particulars 
concerning his system of working, during a long series 
of years, at his famous tanneries at Prattsville, N.Y., 
from which we make the following interesting: extracts : — 



246 LEATHER MANUFACTURE. 

" Since I first commenced business, the gain in weight, 
in converting hides into leather, has been increased nearly 
50 per cent. That is, from a quarter to a third more 
leather can now be obtained from a given quantity of 
hides than at the time when I learnt my trade at my 
father's tannery, conducted in the old-fashioned way. 
The great improvement in weight seems to have been 
gained by the judicious use of strong liquors or ' ooze,' 
obtained from finery- ground bark, and by skilful tanning. 
The loss and wastage upon hides, from hair, flesh, &c, 
may be estimated at from 12 to 15 per cent. In order to 
produce heavy weights, the hides should not be reduced 
too low in the beam house, and should be tanned quickly 
with good strong liquors, particularly in the latter stage of 
the operation. To green hides particularly, nothing can 
be more injurious than to suffer them to remain too long 
in weak ooze. They become too much reduced, grow soft, 
flat, and flabby, lose a portion of their gelatine, and refuse 
to ' plump up.' On the other hand, the effects of an early 
application of ooze that is too strong and too warm to 
green hides is very injurious. It contracts the surface 
and fibres of the skin, tanning at once the exterior layers 
so ' dead,' as it is termed, as to shut up the pores and 
prevent the tannin from penetrating the interior. This 
renders the leather harsh and brittle. It will be seen 
from this that, in the question of the proper strength of 
liquor alone, there is room for the exercise of the greatest 
judgment and the most extensive experience. In the 
impossibility of adapting fixed rules to the innumerable 
variety of cases, nothing can be depended upon but the 
judgment of the practical tanner. 

" In softening hides and preparing them for the process 
of tanning, a great deal depends upon the judgment of 
the person superintending the operation, inasmuch as the 
diversities in the qualities and characteristics of the hides 
render it impossible to subject them to any more than a 
general mode of treatment. In ' sweating,' the character 
of the hides and the temperature are essential but ever- 
varying considerations. As a general rule, however, the 



HEMLOCK TANNING. 247 

milder the process of preparing the hides for the bark 
the better. Unnecessarily severe or prolonged treatment 
is inevitably attended with loss of gelatine, and a conse- 
quent loss of weight and strength in the leather. Too 
high a temperature is particularly to be avoided. In 
almost every lot of hides, particularly Orinocos, however, 
there are generally some that prove very intractable, 
resisting all the ordinary modes of softening. For such, 
a solution of ashes, potash, or even common salt, will be 
found to be beneficial, and peculiarly so in hot weather. 
As I have said, no precise rule can be given as to the 
length o£ time required for the preliminary processes of 
soaking and ' sweating,' so much depending upon the 
qualities of the hides and the temperature at which these 
operations are conducted. 

" The following table may, however, be found useful in 
conveying an approximation to a definite idea of the 
practice in my tannery : — 

Soaking — 

Temperature: 40° 50° 60° 70° 

Days. Days. Days. Days. 

Buenos Ayres hides 10 to 12 8 to 12 6 to 8 3 to 6 

Carthagena and Laguaira . . 8 „ 12 7 „ 9 5 „ 7 2 „ 3 

Sweating — 

Buenos Ayres hides 15 „ 20 12 „ 16 8 „ 12 2 „ 3 

Carthagena and Laguaira ..15 „ 20 10 „ 15 6 „ 8 2 „ 3 

" I would here remark that I changed the process of 
liming to sweating in 1836 — the only change in tanning 
I have made in twenty years ; and for heavy sole leather 
it has been proved to be quite as good as liming, if not 
better, and somewhat cheaper, besides yielding a greater 
gain in weight, and, when well tanned, making leather 
more impervious to water. Liming and bating, however, 
for upper and light leather, is preferable, and if the same 
improvements had been adopted with the lime process of 
strong liquid and quick tanning, it is not yet certain 
that the same results would not have been attained. 

" Salted hides do not require more than two-thirds the 
time to soak, but generally longer to sweat. After the 



*4* LEATHER MANUFACTURE. 

hides are prepared for tanning, the next process is what 
is commonly called ' handling,' which should be performed 
two or three times a day, in a weak ooze, until the grain 
is coloured. New liquors, or a mixture of new and old, 
are preferable for Spanish or dry hides, old liquors for 
slaughters. They are then, after a fortnight, laid away 
in bark, and changed once in two or four weeks, until 
tanned. Much care and judgment are necessary in pro- 
portioning the continually increasing strength of the 
liquors to the requirements of the leather in the different 
stages of the process. The liquors should also be kept as 
cool as possible, within certain limits, but ought never to 
exceed a temperature of 80° ; in fact, a much lower tem- 
perature is the maximum point if the liquor is very 
strong, too high a heat, with a liquor too strongly charged 
with the tanning principle, being invariably injurious to 
the life and colour of the leather. From this it would 
seem that time is an essential element in the process of 
tanning, and that we cannot make up for the want of it 
by increasing the strength of liquor or raising the tem- 
perature at which the process is conducted, any more than 
we can fatten an ox or a horse by giving him more than 
he can eat. 

"I have mentioned the injurious effects resulting from 
too strong a solution of the active principle of the bark ; 
on the other hand, the use of too weak solutions is to be 
avoided. Hides that are treated with liquor below the 
proper strength become relaxed in their texture, and lose 
a portion of their gelatine ; the leather necessarily loses 
in weight and compactness, and is much more porous and 
pervious to water. The warmer these weak solutions are 
applied the greater is the loss of gelatine. To ascertain 
whether a portion of weak liquor contains any gelatine in 
solution, it is only necessary to strain a little of it into a 
glass, and then add a small quantity of a stronger liquor. 
The excess of tannin in the strong, seizing upon the dis- 
solved gelatine in the w T eak liquor, will combine with it and 
be precipitated in flakes of a dark curdled appearance to the 
bottom. At the Prattsville tannery the greatest strength 



HEMLOCK TANNING. 249 

of liquor used for handling, as indicated by Pike's barko- 
meter, is 16° ; of that employed for laying away, the 
greatest strength varies from 30° to 45°. 

"After the leather has been thoroughly tanned and 
rinsed or scrubbed by a brush, machine, or broom, it will 
tend very much to improve its colour and pliability to 
stack it up in piles and allow it to sweat until it becomes 
a little slippery from a kind of mucus that collects upon 
its surface. A little oil added at this stage of the process, 
or just before rolling, is found to be very useful. Great 
caution is necessary in the admission of air in drying when 
first hung up to dry. No more air than is sufficient to 
keep the sides from moulding should be allowed. Too 
much air — or, in other words, if dried too rapidly in a 
current of air — will injure the colour, giving a darker hue, 
and rendering the leather harsh and brittle. To insure 
that the thick parts, or butts, shall roll smooth and even 
with the rest of the piece, it is necessary that the leather 
should be partially dried before wetting down for rolling, 
and that when wet down it should lay long enough for 
every side to become equally damp throughout." 

The average time for tanning by hemlock, in America, 
amounts to five months twenty-seven days ; sole leather, 
however, occupies from four to six months, according to 
the strength of the liquor used and number of sides in the 
vats, and, according to Pratt, the quicker the tanning is 
effected the better is the result. 

Hemlock Tanning of New Lebanon, M\J. — Dussauce 
gives the following description of the process of tanning 
with hemlock at the Shaker tannery of New Lebanon, as 
furnished to him by the Shaker tanner, Mr. Fred. Sizer. 
" I take a pack of calf skins — say 100 dry skins — and put 
them in a water vat to soak ; after they have soaked two 
or three days I take them out and mill them (a wheel is 
best for milling hides) ; I then beam them on the flesh 
side, removing all the lean meat and grease from the 
skins, stretching them out well with the beaming-knife, 
and put these into a vat of clean water until they are soft 
enough to go into the lime. They must be as soft as 



250 LEATHER MANUFACTURE. 

when they came from the animal, or as near that as you 
can get them. If the hides are not soft before going into 
the lime, they never can be, and the leather will always 
be hard. 

"Fresh hides, that come direct from the butchers, are 
put in water a day or two ; change the water once, beam 
them on the flesh side ; they are then ready for the lime. 
I make my lime in a vat 8 feet long by 4 wide and 4 deep. 
One bushel of lime and 2 gallons of soft soap put in the vat 
two-thirds full of water will make a lime sufficient for 
100 calf skins or five sides of upper leather. The hides 
should be handled out every other day, while in the lime, 
to air and change their position ; then stir the lime well 
before they are put back. The lime needs strengthening 
every time a new pack is put in by adding, say half-a- 
bushel of lime and two or three quarts of soap. I lime 
my calf skins and upper leather hides until the hair comes 
off easily, but sole leather hides should be limed as little 
as possible to get the hair off ; then unhair them, wash 
them out in the mill, beam them on the flesh side, trim 
off the pates and shanks, and put them in the bate. 

" I put five or six bushels of hens' dung into a vat of the 
same dimensions as used for the lime and till two-thirds full 
of water and let it stand two or three days to ferment. I let 
my skins remain in the bate two or three days in warm 
weather and longer in cold ; haul them two or three times 
while in the bate, and work them twice on the grain with 
a common worker on the tanner's beam ; mill them before 
working the last time, then beam them, and they are 
ready for the tan-vats. I make a liquor of moderate 
strength to handle them in, put them in this liquor, and 
stir them with a pole a while, then handle them up smooth 
on a box or rack three or four times in the course of the 
day; let them remain in this until the next morning, then 
change the liquor, giving them about the same strength 
as at first ; handle them two or three times a day in the 
liquor, and when this is exhausted change again, and 
handle less as the skins get coloured and the grain set. 
" I make my liquors of hemlock-bark, ground and put 



HEMLOCK TANNING. 251 

in leaches, and pump in the exhausted liquor. The first 
strength of my leaches I draw off the sole leather vats. I 
draw off the leaches two or three times before taking it 
from my upper leather and calf skins, and these I keep in 
mild, sweet liquors through the whole tanning process. I 
handle my hides and calf skins through until tanned, 
changing the Kquors as they get exhausted. After they 
get well along I handle them three times a week. They 
will do to lay longer, but will tan faster if handled often. 
When my calf skins have been in the tan two or three 
weeks I shave clown the necks, and after my upper 
leather, has been in four or five weeks I shave it down to 
a proper thickness. 

" In my experience in tanning, which has extended 
through forty-two years, I have used both hemlock and 
oak bark, and I find that mild sweet liquors are far best 
for tanning all kinds of upper leather. The hide in the 
raw state is tougher than when tanned, and that toughness 
ought to be preserved as much as possible, to make good 
pliable leather, and the slow process of tanning with mild 
liquors will do it. Strong liquors have a tendency to 
make the leather hard and liable to crack. The hides for 
upper leather should not be tanned any more than 
thoroughly through; if tanned longer than this it has 
the same effect upon them as strong liquor ; but the 
longer sole leather is tanned the better. When I think 
my leather is nearly struck through I try it by cutting 
into the thickest edge, and when tanned through take it 
up and scour it out on the wheel to cleanse it from the tan 
and soften the grain ; then take them to the currying 
shop, and the calf skins I skive, and uppers smooth down 
with the currying knife ; then put them in a tub of water 
and scour them on the table with a brush, stone, and 
slicker ; dry them a little, temper them, and then put 
them on the table and set them on the grain side to work 
the grain out smooth. After that apply some thin stuff- 
ing made of oil and tallow, then turn them over, flesh side 
up, and set them out with an iron slicker ; then apply the 
stuffing more plentifully, made thicker with more tallcw ; 



252 LEATHER MANUFACTURE. 

then hang them on sticks and dry them, and then pack 
them down in a pile, and let them stay two weeks. I 
then take them and rub off what stuffing does not strike 
in, and whiten them with a currying knife or slicker. 
I commonly whiten my calf skin and kips with a slicker, 
and finish in the French style. Since the French degras 
has come into use, I have used it for calf skins and kips. 
I have also for some time used tansy in my liquors. 
There is an acid in tan that injures the leather which 
tansy neutralises and keeps the liquor sweet." 
Hibberd's Process. — This process consists — 
First, in the use of a compound of lime, wood ashes, 
or potash, and salt for removing the hair or wool, and 
also for the purpose of so-called " liming," instead of 
using the lime alone. Lime and ashes have been used 
separately for the purpose of removing the hair, wool, 
&c, but lime alone requires several days, and in cold 
weather weeks, to effect these objects, by which, the 
inventor says, the skin is more or less injured. " On 
the other hand, ashes alone act too rapidly, and would 
destroy the skins altogether. When lime, ashes, and 
salt are combined in proper proportions, the salt modifies 
the action of the alkalies, and protects the skin from 
their caustic properties, so that the process of unhairing 
and liming are both rendered more expeditious and safe 
than by the old method, while the texture of the skin is 
uninjured, and consequently the leather is much stronger." 
Second, in the use of a composition of salt, sulphuric 
acid and sumac, oak, hemlock-bark, or other tanning 
material for the process of tanning. The salt, sulphuric 
acid and tannin being mixed together in water in certain 
proportions hereafter mentioned, a portion of the salt is 
decomposed by the acid, forming sulphate of soda, and 
setting free muriatic acid, which acid, being absorbed by 
the water, acts directly and rapidly on the skins, opening 
their pores, and preparing them for the tannin, which, 
being present also in the mixture, immediately and readily 
unites with the gelatine of the skin, forming leather more 
expeditiously and perfectly than by the usual methods. 



HEMLOCK TANNING. 253 

Preparation of the Skins. — By this process the skins 
may be prepared as usual, but the inventor prefers to 
employ the following-, which he calls composition No. 1 : — 

Quicklime, fresh slaked J bushel. 

Wood ashes J ,, 

Common salt 3 pints. 

For the ashes may be substituted from 3 lbs. to 5 lbs. 
of potash. 

To remove the hair or wool, the above composition is to 
be mixed with sufficient water to make a thick paste, and 
applied to the flesh side of the hides in the usual way, the 
skins to be folded and kepfc at a temperature of summer- 
heat. In a few hours they will be ready to pull. For 
" liming " or " ashing," he uses the same composition, 
No. 1, mixed with a sufficient quantity of water in a vat 
to immerse the number of skins required to be treated. 
One bushel of the mixture is equivalent to one bushel of 
lime alone. The liming and ashing process may be con- 
ducted at a temperature of 40° to 60° Fahr. 

Composition for Tanning. — For six dozen full-sized sheep, 
deer, goat, or similar skins of the same size : — 

Common salt 18 lbs. 

Sulphuric acid 2 ,, 

Sicily sumac, or quercitron bark 36 „ 

Muriatic acid 2 ounces. 

Dried clover , . . . . 18 lbs. 

Soft water 150 gallons. 

The sumac or dyestuffs are first exhausted with water, 
and then the salt is added to the liquor, apportioned so as 
to ensure perfect solution. The acids are afterwards added, 
and the mixture thoroughly incorporated by stirring. 



CIIAPTER XX 

TANNING BY ELECTRICITY. 

Ward's Process. — Gaulard's Process. — G-aulard's Second Process.— 
Meriten's Process. — Crosse's Process. 

Tanning by Electricity.— Considering the many pur- 
poses to which the electric current has been applied, and 
the growing belief that this remarkable force is yet sus- 
ceptible of many applications in the arts, it is not to be 
wondered at that endeavours should be made to utilise 
the current in the process of tanning. Whether success 
will attend the employment of electricity in the tannery 
has yet to be determined, and this, of course, can only be 
done by careful and unprej udiced trial. The time has come, 
we hope, when manufacturers cease to ignore new modes 
of procedure merely on the ground that they are novel. 

Ward's Process. — The inventor states that the object 
of his invention is " the tanning of hides and skins by a 
more speedy and efficient process than heretofore, in suit- 
ably arranged vats or tanks, by the aid of electricity," 
and it is effected in the following manner : he employs 
the ordinary vats or tanks, which are lined with india- 
rubber cloth, or other non-conducting substance. The 
vats are filled with tan liquor, and the hides suspended 
therein. The electric current is obtained by means of a 
suitable battery. The effect of this, he states, is that the 
current passes through the whole contents of the vats, 
and the tanning process instantly commences, and con- 
tinues until the strength of the liquor is absorbed, when, 
if desired, fresh liquor may be added, and the current 
again applied. By this means, the inventor states, hides 

X 



TANNING BY ELECTRICITY. 



255 



and skins "may be fully and effectually tanned in the 
space of a few hours." 

Gaulard's Process. — The inventor says, " Various ob- 
servations on the tanning of skins having demonstrated 
that the reaction produced has been the decomposition of 
the watery juice by the tannin, which seizes the oxygen, 
whilst the hydrogen acts on the nitrogenous matter and 
destroys it in changing it into ammoniacal salts, I have 
concluded that for causing a rapid tanning it suffices to 




Pig. 45. 

oxidise the tannin and destroy the nitrogenous matter by 
causing to intervene an electric current into the juice, 
which decomposes the water of the liquor into oxygen and 
hydrogen, and determines at the same time with rapidity 
the reaction above mentioned." 

In carrying out the process the hides or skins are dis- 
posed as shown in the accompanying drawing. Fig. 45 
is a tub a ; on the upper floor b of the double bottom b b 1 , 
the hides are stratified in the usual way, that is to say, 
with alternate layers of the hides or skins and tannin. In 
the space between the two floors of the double bottom b b 1 



256 



LEATHER MANUFACTURE. 



are placed two parallel charcoal blocks C c, fixed by the 
aid of copper clamps d d. The two charcoal blocks c 
are put into communication by means of the wires a and 6 
with the two poles of any electric generator, whereupon 
the decomposition of the watery juice into its two elements, 
oxygen and hydrogon, takes place, and the rapid assimila- 
tion of the tannin and the hides or skins is effected. 

Gaulard's Second Process. — Referring to the former 
patent by the same inventor, the patentee says, " Instead 
of placing both poles [of the electric generator] in the 




Fisr. 46. 



middle of the vessel, and thus causing the two gases 
evolved by the decomposition of the water [oxygen and 
hydrogen] to act simultaneously, one only of the elec- 
trodes is placed in the centre of the vessel, the other 
being arranged in a parallel plane, but in a corner, and in 
the centre of a passage or conduit, arranged as illustrated 
(see Fig. 46) in the drawing, that is to say, extending to 
about four inches from the bottom of the vessel. The vessel 
is filled with weak liquor, and the hides are suspended 
therein from wooden crossbars resting on the sides of the 
vessel. The electric current is then caused to pass in such 
a manner that the negative pole is in the centre of the 
vessel and the positive pole is in the ' conduit.-' Under 



TANNING BY ELECTRICITY. 



257 



these conditions the hydrogen alone acts upon the leather, 
and causes the rapid destruction of the nitrogenous 
matter contained therein. After undergoing this treat- 
ment for eight daj r s, the liquor is changed for a stronger 
tanning solution. The current is then reversed, so that 
the pole in the middle of the vessel becomes the positive 
pole and the pole in the conduit the negative. The 
oxygen alone then acts upon the liquid, inducing a rapid 
oxidation of the tannin, and its precipitation in this con- 
dition in the cells formed by the gelatine and fibrine of 




Fig. 47. 

the hide. The hydrogen escapes into the air through the 
conduit. Under these conditions the tannin is effected in 
about fifteen days, and, in order to make the leather more 
weighty, a stronger liquor must be employed, or the hides 
may be stratified with layers of tan, as in the ordinary 
method, at the same time keeping up the electrical action. 
A wooden grating, arranged at a height of about eight 
inches from the bottom of the vessel, is employed to keep 
the electrodes from direct contact with the leather, as 
shown in the engraving, Fig. 47." 

Meriten's Process. — The bottom of the tan-pit is 
composed of a block or slab of conducting carbon or char- 

s 



258 LEATHER MANUFACTURE. 

coal, or of two or more such blocks or slabs, covered with 
a layer of the same substance in a coarse powder. A 
copper wire coated with gutta-percha or other insulating 
material is employed, one end of which is connected to the 
carbon, and the other end, being carried up the side of 
the pit to the exterior, is connected to the positive pole 
of a battery. Upon the bottom so constructed, there is 
placed a layer of bark or other tanning material, suf- 
ficiently impregnated with water, and above this a hide or 
skin, then another layer of bark or other tanning material, 
then another hide, and so on in alternate succession to 
any required number. A sheet or plate of zinc, in con- 
nection with the negative pole of the battery, is disposed 
at the upper part of the pit, and rests upon a layer of the 
tanning material, and above the zinc there is placed a 
final layer of tanning material sufficiently impregnated 
with liquid as before. " On establishing an electric cur- 
rent, a motion takes place between the two poles through 
the hides or skins, the basic elements proceeding to the 
negative pole and the acid elements to the positive pole, 
whereby a molecular motion is produced and maintained 
throughout the hides or skins, and the fixing of tannin in 
their pores is effected. It is preferred to divide each of 
the poles into two or more surfaces, according to the 
depth of the pits and the quantity of hides which they 
contain ; but it is in all cases essential that the anode 
{positive pole) should be composed of an insoluble ma- 
terial." This of course means carbon, or some metal not 
acted upon by the tanning liquor when decomposed by 
the current. • 

Crosse's Process — This process has for its object First, 
the unhairing of hides and skins, by the employment of 
sulphide of lime, in which the hides are soaked, when the 
hair becomes loosened and may be removed in the usual 
way. Second, in producing electric effects on the matters 
in the tan-pit. On one side of the pit is placed a plate 
of lead, and on the other a plate of zinc, the plates cover- 
ing the sides of the pit. The two plates are connected at 
the upper parts above the liquid by a band of either 



TANNING BY ELECTRICITY. 259 

metal. The skins are suspended in the pit, filled with 
water, and remain three or four days. The water is then 
removed or converted into ooze or tanning liquor, by- 
adding bark or other suitable matter, or the water is 
replaced by tanning liquor of a strength equal to about 
15° of a saccharometer, and the liquor is kept up at that 
strength for a week. The strength may be then increased 
to 5° a week till it reaches 45°. The process may be 
varied, and the strength and progressive increase of 
strength in the tanning liquor modified. 



CHAPTER XXI. 

CHEMICAL TANNING. 

Knapp's Processes. — Heinzerling's Chrome Process. — Heinzerling's 
Second Chrome Process. — Vanderstraaten's Process. 

We have been tempted to adopt the above heading to dis- 
tinguish the processes about to be described from the ordi- 
nary processes of tanning, to which they may be said to 
have no resemblance. Whether the manufacture of leather 
by other agents than tannin will ever become really suc- 
cessful is a question which time alone can decide.* We 
know that alum and salt, as employed in the process of 
tawing, produce a certain effect upon the skins of smaller 
animals — as the calf, sheep, goat, &c. — which renders 
them suitable for certain purposes to which leather, properly 
so called, would be wholly unfit ; but whether a substitute 
for tannic acid in the manufacture of leather from heavy 
hides will ever be discovered, is a matter upon which few 
will venture to prophesy " onless they know," as Artemus 
Ward put it. Many attempts have been made in this 
direction, and we may hazard the prediction that even if 
a better article could be produced without the agency of 
tannin, it would take a very long time before the world 
— so long accustomed to the smell of tan — would believe 
in it. 

From the numerous processes which have been patented, 
we select several which have to some extent commanded 
attention, and at least one of which has been worked upon 
a practical scale: we allude to what is known as the 
chrome-tanned leather process of Dr. Heinzerling, carried 
out by the Eglinton Chemical Company, of Glasgow. 

* The chrome process is now an acknowledged commercial success for 
most of the lighter kinds of upper leather, and is also used to some 
extent for harness and belting leather. — Ed. Fifth Edition. 



CHEMICAL TANNING. 261 

Knapp's Processes. — I. By this process, which, was 
patented in 1877, an oxide salt of iron is prepared in the 
following manner : To a boiling solution of green vitriol 
(sulphate of iron) as much nitric acid is added as will 
thoroughly oxidise the same. The effervescence which 
takes place being over, the operation is reversed, green 
vitriol being added to the solution now containing the 
iron oxide ; the second ebullition or effervescence caused 
by this operation having subsided, the compound has now 
a syrupy consistence, and is of a yellow-red colour. If it 
be slowly evaporated, there remains the dry iron oxide 
salt as an, orange-red transparent varnish. Basic sulphate 
of iron manufactured in this way is very different in its 
physical properties from that of commerce and described 
in chemical books. This latter does not give a syrupy 
solution, and is of a much darker colour — a brown-yellow 
— and decomposes on being boiled in an aqueous solution. 
On the other hand, the preparation above described may 
be boiled in a solution of 30° to 40° Baume without decom- 
posing, and is in reality copiously taken up by the skins 
of animals. 

II. To carry out this process, the hides are treated with 
the above iron salt in the following way : — 

First Dressing. — To prepare the hides, they are placed 
in a cold solution of the iron oxide salt, and the dressing 
is thus completed in two, or at the most four, days, accord- 
ing to the quantity of skins or hides treated at once. 
Relaying the skins, handling, and other like operations 
are dispensed with. 

Currying. — After the skins have been tanned (!) with 
the iron salt solution, they are treated with fats and 
greases in a liquid state, and with a new "iron soap" 
described further on. The greases are dissolved in the 
manner now in use, and the leather soaked with them, or 
" stuffed," after the skins have been sufficiently dried. In 
this manner the present expensive and tedious hand mani- 
pulation, which makes the value of leather so dependent on 
the skill and attention of the workmen, is quite done away 
with ; that is to say, the greasing of the leather by hand 



262 LEATHER MANUFACTURE. 

with greases, fat, and like substances, the hanging up in 
the drying-room, the tramping in the drum, and the 
working off of the superabundant greases, is thus done 
away with. Besides the greases now in use, the inventor 
employs stearine and paraffin, which are chemically dis- 
solved in the usual way. By the use of fats in combina- 
tion with the iron solution, the substances used for greasing 
the leather are united in such a way on the fibres of the 
skin as to form an " iron soap," which is an entirely new 
product. 

The iron soap is produced by precipitating soap from its 
solution by means of the afore-mentioned iron salt solu- 
tion. The iron soap, combined or not with fatty emulsions, 
is worked into the leather by means of a drum. This 
drum consists of a tramping drum, which revolves round 
a hollow axle, this latter being connected with a blower 
by a pipe. The blower drives the air through the hollow 
axle, and through pipes to the circumference of the 
tramping drum, and through the hides. 

III. In this process a solution of sulphate of peroxide 
of iron is produced, which acts in the same manner as the 
solution before described, but with better effect in tanning. 
Moreover, it is chemically a different compound. This 
solution is produced by adding equivalent quantities of 
sulphuric acid and nitrate of soda, instead of nitric acid, to 
the boiling solution of the sulphate of iron. With the 
exception of these substitutions, this solution is to be 
treated in the same way as before. The solution differs 
from the former chiefly by the soda of the nitrate of soda 
entering into the new compound as a constituent part, 
along with the peroxide of iron and the sulphuric acid. 

IY. In this process the inventor treats the leather with 
albuminous matters, as blood, &c, in such a way that they 
form a precipitate and compound with the peroxide of iron 
of the "tanning" salt before described. 

Heinzerling's Chrome Process. — The hides are un- 
h aired and soaked in the usual way, after which they are 
placed in a solution of from 1 to 5 per cent, of acid or 
neutral chromate of potash, chromate of soda, or chromate 



CHEMICAL TANNING. 263 

of magnesia, and from 1 to 10 per cent, of alum, or a 
corresponding quantity of sulphate of alumina. To these 
may be added from 1 to 10 per cent, of chloride of sodium 
(common salt). In this bath the skins are left a longer or 
shorter time, according to their texture and thickness. 
After the hides have been in the solution for some days, a 
small percentage of yellow or red prussiate of potash is 
added, or may be introduced at the commencement of the 
operation. The prussiate of potash is preferably used for 
leather which is afterwards to be blackened, and may be 
dispensed with for other leather. In order to fix the 
tanning. (!) stuffs in the leather, manipulated as above 
described, the hides should be placed for a short time in a 
solution consisting of 1 or 2 per cent, of chloride of barium, 
1 or 2 per cent, of acetate of lead, or the same proportion 
of soap. The hides can be dried in the usual manner. 

The smooth, damp hides are next dipped for a short 
time in stearine, paraffin, chrysene or naphthaline, resin, 
or other like stuffs, the same having been dissolved in 
benzine, photogen, or other like solvents. To the above 
may be added some carbolic acid or thyme oil. The 
greasing can be effected as usual. The new leather is said 
to be practically watertight, and when required, is made 
much softer and more lasting than ordinary leather, while 
the cost is stated to be much lower than by the bark 
process. 

Heinzerling's Second Chrome Process — In this pro- 
cess the inventor employs other chrome compounds than 
those mentioned in the preceding process, as also certain 
other substances which he has found to be effective in 
preparing leather by his method. He says, " I have found, 
too, in experimenting, that there are many chrome com- 
pounds besides chromate of potash or magnesia that are 
effective. Thus, chromic acid, the other soluble chromates, 
especially those of ammonium, aluminium, and iron, or 
the sulphate, chloride, acetate, and other soluble chromium 
salts, are all efficacious for the purpose of converting skins 
or hides into leather. I also find that the precipitation 
of soft white neutral mineral material in the pores of the 



264 LEATHER MANUFACTURE. 

leather is very advantageous in preserving it, improving 
its colour, and making it impervious to moisture. Further, 
that the addition of such salts or oxides as the sulphates 
of copper, manganese, and zinc, chloride and borate of 
zinc, tungstate of sodium or of potassium, sulphate or 
chloride of protoxide or sesquioxide of iron, and oxide 
of manganese, improve the texture, durability, and colour 
of the leather." The inventor then gives the process as 
actually practised by him in Germany, and which is, we 
presume, the same as that which has been adopted by the 
Eglinton Chemical Company, of Glasgow. 

"The hides being unhaired in the usual manner, I put 
them first in a weak, and after a few days in a stronger 
solution of a soluble chromate or chromic acid. To this 
solution I add a soluble salt of aluminium, or the soluble 
hydrated oxide which is formed when carbonate of soda is 
added to a solution of alum. The quantity of aluminous 
matter in solution depends on the texture of the hides, 
the density of leather required, and the salts used ; it 
varies, therefore, from nothing to say four parts by weight 
of oxide of aluminium to one hundred of water. The 
quantity of chromium salt used varies from half to five 
parts to one hundred of water. In the first pit both the 
chromic and aluminous materials are weak, especially the 
latter. While in succeeding pits the chrome does not vary 
much, that of the aluminous matter varies widely, sole and 
other hard leathers requiring large quantities, whereas 
washleather and thin uppers require none, or very little. 
During the cold season the pits can be moderately heated, 
say 30° C. (86° Fahr.) The hides are left in this chrome 
and aluminous solution, with or without the addition of 
any of the above-mentioned metallic salts useful for im- 
proving the colour or for tanning, from one to twenty days, 
according to size, texture, and thickness of the hides, 
until they are perfectly converted. Their progress and 
complete conversion may be easily tested by cutting off a 
piece and seeing if the tanning liquor has thoroughly 
penetrated it. After this they are put into a solution of, 
say from three to eight per cent, of a soluble carbonate, 



CHEMICAL TANNING. 265 

such as carbonate of sodium or potassium, or a solution of 
soluble soap, say three to six per cent., in order to fix super- 
ficially the tanning materials. In some cases it is advan- 
tageous to use, instead of the above bath, a soluble barium 
salt, such as the chloride, especially when alum or other 
sulphates have been largely used. 

" Instead of treating the hides with carbonate of sodium 
or soap in solution, as before mentioned, in some cases it 
may be advantageous to use albuminous matter, such as 
the serum of blood, either dissolved in acids or alkalies, or 
in the solid state, finely divided, as it is used in the kid 
leather manufactories. The hides are either immersed for 
a certain time till the matter has entered superficially, if a 
solution be used, or tramped in a tramping tun for an 
hour, in order to facilitate the mechanical entering of the 
albuminous matter. 

" The hides intended for upper or belt leather are now 
dried till they are merely damp, and then stretched ; those 
for sole leather are made quite dry. They are then put 
into a solution of paraffin, stearine, colophony, or the like 
(dissolved in any suitable solvent, such as benzole or pho- 
togen), or into vegetable or animal wax, or such stuff as 
that formed from treating rape or linseed oil with ten to 
eighteen per cent, of chloride of sulphur, or the solid 
soluble residues which are obtained in petroleum and 
paraffin refineries, or varnish and birch- tar oil ; the above 
solution is heated from 26° to 38° C. (about 76° to 100° F.) in 
a water-bath before and whilst the hides are in. The hides 
are kept in this bath preferably at from 28° to 30° C. (about 
86° F.) for from one to three days, according to size, texture, 
and thickness ; they are then exposed to the light for 
twenty-five to sixty days, until the stearine, paraffin, colo- 
phony, or other hydro-carbon used appears oxidised 
throughout Upper and belt leather can be greased a 
second time if required with the usual substances or 
with vaseline. The above-described stuffs may be also 
used in the melted state if they are fusible at a low tem- 
perature. 

"After a certain quantity of hides have been tanned, it 



266 LEATHER MANUFACTURE. 

will be found advantageous, instead of adding soluble 
aluminous salts, to add a quantity (proportional to the 
acids set free) of basic aluminium compounds got by in- 
complete precipitation of aluminium salts with carbonate 
of sodium or ammonium, or of hydrate of alumina. The 
tanning liquor should be analysed from time to time, and 
the mixture kept up to standard chemical composition." 

Vanderstraaten's Process. — The following is a brief 
outline of the process, the inventor being a Belgian tan- 
ner : — The hides, after being cleansed from all materials 
incidental to the removal of the hair, are put into a bath 
of vegetable tannin of a certain strength, which prepares 
them for the succeeding treatment. The bath is made 
from valonia or similar vegetable substances, and if twelve 
hides are to be treated at one operation, in a vat holding 
about six cubic metres, five kilogrammes of valonia are 
required. This is first boiled in order to extract all the 
tannin. The hides remain in this bath one day, and 
another day in a second bath, which is made a little 
stronger than the first. The baths can be used over again 
by adding fresh material until they are of the desired 
strength. This first tanning gives to the leather an iron- 
grey colour. The second operation is performed by means 
of bichromate of potash, which turns the iron-grey 
colour into a mahogany-brown. If a lighter shade is 
desired, half the valonia of the first process is replaced by 
a corresponding quantity of mimosa-bark. The colour of 
the leather can thus be determined at the will of the 
tanner by varying the quantity of tanning material, the 
strength of the mixture, and the time consumed in the 
operation. The hides, which are so far only superficially 
tanned, are then immersed in a solution of either alum, 
sulphate of silicon, chromate of potash, salts of iron, or 
other similar astringent agents. 

The inventor claims no right to any of the tanning 
processes by minerals, but confines himself to the following, 
preferring the use of bichromate of potash ; the hides are 
immersed in a weak solution of this salt, and frequently 
taken out and turned, so that the chemical action which 



CHEMICAL TANNING. 267 

produces the grain and colour may be uniform. For this 
purpose one or two hours are generally sufficient. If the 
operation is successful, a fine grain, soft to the touch, is 
formed, and a moderate swelling can be seen. The colour 
becomes permanent, and can no longer be changed. In 
the first weak bath they are suspended and subjected to 
a gentle motion ; here they remain until the tanning 
material has thoroughly penetrated the skin, which gene- 
rally occurs after from twelve to fifteen days. The hides 
are then taken out, thoroughly washed, and subjected to 
strong hydraulic pressure, by which means most of the 
chrome, liquor is forced out of the leather, while some of 
it remains, and this has to be rendered insoluble, which is 
done by a gelatine treatment. The hides, as soon as they 
leave the press, are dipped into a bath of hot gelatine, 
made from the offal of fresh leather, until they are 
thoroughly impregnated with it, and after this are placed 
in an agitator for about an hour, by which time the gelatine 
will have been absorbed by the leather. This treatment 
renders both the bichromate of potash and the gelatine 
insoluble, and strengthens the leather by replacing the 
natural gelatine which had been extracted in the earlier 
operations of the process. 



CHAPTER XXII. 

MISCELLANEO US PB CESSES. 

Indian Method of Preparing Elk-skins. — Old Irish Process of Tanning. — 
Tanning Nets, Sails, and Cordage. — Glycerine in Tanning. — Bleach- 
ing Leather. 

Indian Method of Preparing Elk-skins. — Immediately 
after the skin is removed from the animal it is spread out 
to dry. The brains are then removed and also dried in 
the sun upon the grass. When the hunting season is 
over, the women prepare the hides by soaking them first 
in water, and afterwards taking off the hair with an old 
knife. The hides are then put into a large earthenware 
vessel containing water, and the brains are then added 
and the vessel heated to about 95°, by which operation 
they become very well cleansed. The skins are next 
wrung out and spread upon a kind of rack formed of two 
upright posts, with two sticks placed horizontally. With 
the assistance of ropes, the women spread them very well, 
and during the drying they rub them continually with a 
stone or round piece of wood, to assist in getting rid of 
the water and grease, till they are quite dry. In one day 
a woman can prepare from eight to ten skins. 

Old Irish Process of Tanning. — This consisted in 
utilising the heath, which grows abundantly in Ireland, 
as a tanning material. The heath was put into a large 
cauldron full of water and allowed to boil for about three 
hours, by which time the tanning principle was exhausted. 
The liquor was afterwards drawn off into large vats and 



MISCELLANEOUS PROCESSES. 269 

the material again treated with water as before. When 
this last liquor had cooled down to about 95°, the skins 
were first immersed in this, and afterwards in liquor of 
increasing strength. In using the liquors the temperature 
should not exceed 95°. A very good leather was produced 
by this process. 

Tanning Nets, Sails, and Cordage. — The following 
method of preserving and increasing the strength of nets, 
sails, and cordage was patented many years ago. A 
hundred pounds of oak branches and the same quantity of 
tan are boiled in eighty-nine gallons of water, until it is 
reduced to seventy-one gallons. The solid materials are 
then taken out, and the articles to be tanned are deposited 
in the liquid, care being taken that they are entirely 
covered by it, and do not rest upon the bottom of the 
vessel. They are boiled for three hours, and are then 
taken out and dried. This, though a true tanning process, 
can scarcely be likened to the ordinary ones for preparing 
leather, since its object is a combination of tannin and 
extractive matter with vegetable substances, which are 
very different from the gelatine of skin. According to 
Millet, linen which had been steeped in an oak-bark 
liquor at 150° Fahr. for two or three days, remained 
unaltered in a damp cellar for ten years, while an 
untanned piece entirely rotted under similar circum- 
stances. 

Glycerine in Tanning. — M. Mene, after first observing 
that glycerine is a substance which has been found by 
experience to be useful as a means of increasing the elas- 
ticity and strength of leather, states that hides, first partly 
tanned by the usual process, may be greatly improved, 
especially if required for machine belts, by being soaked 
for some time in glycerine. 

Bleaching Leather. — One might naturally think that 
when leather possesses all the characteristics of solidity, 
firmness, and toughness, being perfectly tanned through- 
out its entire substance, that its colour would be a matter 
of little concern. That this is not so, however, is well 
known, and any divergence from the Ian colour proper 



270 LEATHER MANUFACTURE. 

is sure to create a prejudice agaiust the leather, be it 
ever so good in all other qualities. This is specially so 
in the case of hemlock-tanned leather, which, unless pre- 
pared with more than ordinary care, or combined with 
other tanning materials to reduce its natural redness, 
presents a colour which, in the eyes of those accustomed 
to the colour of oak-tanned leather, is objectionable in 
the extreme. To overcome this well-known prejudice 
against hemlock tannage, many ingenious persons have 
turned their attention, with the result that certain 
bleaching processes have been introduced into the United 
States, for the details of which we are indebted to 
Mr. Jackson Schultz, who, however, does not commend 
this system of tampering with leather in the processes of 
finishing. 

By one process of bleaching sugar of lead and sulphuric 
acid are employed. "The practice is to dip the sides 
alternately, first into the bath of the one and then into 
the other, until the colouring matter of the hemlock is 
fully removed. This bleaching process gives an imme- 
diate, that is almost magical, result ; but when the finished 
leather is exposed to the air and light for any considerable 
time, the delicate pink and cream colour turns to a ' murky 
brown,' and is in all respects a most objectionable finish. 
The only natural and honest bleaching process known to 
the writer is that of ' sumac baths.' After the hemlock 
sides have been cleansed of all extraneous matter by the 
most effective mechanical device known, they must then 
be hung in a vat of warm sumac liquor, and plunged fre- 
quently for one day — even a few hours will sensibly affect 
the colour. Usually one bag of Virginia sumac will 
suffice for a pack of one hundred sides. This process will 
cost about five dollars for a pack, or five cents per side 
weighing 15 lbs. to 20 lbs. The sumac liquor forms a 
vegetable acid, which acts most kindly on the grain of 
hemlock slaughter leather, not only removing (neutra- 
lising) the colour, but softening the grain, and contributes 
very much to the whiteness and clearness of the buff." 
Mr. Schultz says that hemlock leather thus treated will 



MISCELLANEOUS PROCESSES. 271 

retain the improved colour for a long time, and " never go 
back to that muddy and objectionable colour so common 
with other bleaching processes." 

" As it is the acid which effects the object sought," Mr. 
Schultz observes, " the sumac should be retained long after 
the tannin has departed. As a mere tanning agent it is 
only valuable, as all goat and sheep skin tanners compre- 
hend, while it is fresh, and before the acid forms. But for 
the purpose of bleaching hemlock leather it is questionable 
whether the old cast-off sumac of the morocco dresser is 
not quite as valuable as new sumac." To this Mr. Schultz 
adds an important suggestion which the users of hemlock 
will doubtless appreciate. " Slaughter hemlock leather, 
tanned with liquors of moderate strength, say 16° to 20°, 
will produce a colour that is between the lemon and the 
orange, and if to this we add the warm sumac process, we 
have then a colour so nearly a light lemon or flesh colour 

as to meet all the requirements of the best oak 

This process is particularly serviceable on calf and all 
grain-finished leathers, including harness and bridle. No 
hemlock tannages will 'take the bleaching' so well 
without as with this process. With it grain leather can 
be made to hold its colour almost equal to a pure oak 
tannage." 

Note. — Sumac is still used extensively for bleaching purposes. Care 
must, however, be used in its application, otherwise the leather so 
treated is likely to lose weight. Sumac appears to possess the property 
of being able to dissolve and withdraw some of the more solid con- 
stituents of the previous tannins used. — Ed. Fifth Edition. 



CHAPTEB XXIII. 

ON THE COST OF AMEBIC AN TANNING. 

Mr. J. Scluiltz on the Cost of Tanning — This obser- 
vant American authority has entered very fully into the 
question of the cost of tanning, and with his usual clear- 
ness of reasoning has shown how variable may be the 
results obtained by manufacturers working under different 
conditions or by different methods of tanning. lie ap- 
proximately estimates the cost of tanning as follows : — 

Hemlock sweat sole leather per lb. from 6 to 7 cents. 

Union lime sole leather „ „ 8 „ 9 „ 

Oak lime leather „ ,, 9 „ 10 ,, 

Oak lime rough leather „ „ 8 „ 9 „ 

Hemlock lime rough leather.... „ „ 6 „ 7 „ 

The cost will differ with the circumstances under which 
the tanning is conducted. One tanner devotes extra 
time to the beam work ; another to the finishing ; an- 
other to the handlers or layers ; the freight and price 
of bark will vary in different localities, therefore in esti- 
mating the cost it is to be understood that an average is 
given. 

One ton (2,240 lbs.) of average hemlock bark will tan 
200 lbs. of sole leather, with the following exceptions : — 
1. If the bark is ground and leached imperfectly, or in 
an extraordinarily perfect manner ; 2. If the leather is 
tanned with a very strong decoction, and thereby a very 
large gain is obtained as against very weak liquors and 
light gain ; 3. Great delays and wastes in applying the 
tannin, which induce the formation of gallic acid ; or the 



COST OF AMERICAN TANNING. 273 

bringing fresh, sweet, strong decoctions into contact with, 
liquor already containing a large percentage of this acid. 
These exceptions will vary the result from 180 lbs. to 
200 lbs. of leather made from one ton of bark. Again, if 
the weight of the delivered bark is not accurate a loss 
will accrue from this cause. 

Mr. Schultz attaches great importance to the strength of 
the liquors employed, as influencing the cost of tanning. 
He says : " The upper leather tanners of New England, 
who pay ten to twelve dollars per cord [or ton] for their 
bark, claim to tan, and probably do tan, from 300 lbs. to 
400 lbs.- of upper leather with 2,240 lbs. of bark. If we 
comprehend how this is possible, it will enlighten us as to 
the point under discussion. The upper leather tanners 
draw their tanning and colour matter from agents which 
furnish about 20 per cent, extractive material, while the 
vigorous sole leather tanner obtains his capital from the 
7 to 8 per cent, tannin which the bark contains. The 
tannin gives all the gain added to the gelatine, but the 
colouring matter permeates the fibre, while cumulative 
gallic acid holds it from decomposition. Upper leather, 
then, is not tanned and filled as sole leather is, and 
to this extent and for this reason bark extract will 
spread itself over far more fibre when all the extractive 
matter is employed than when it is manufactured so as to 
hold only tannin pure and simple. It must be evident 
that when skins are tanned quickly in strong liquors it is 
at the expense of the most costly agent (the tannin), 
while the vegetable extractive (the cheaper material) does 
not enter the skin to any appreciable extent. Conse- 
quently, if we are to accept Davy's view, the leather 
produced, while being extravagantly filled with tannin, 
will be deficient in one of its most important constituents 
(extractive), and therefore inferior in quality and of less 
value than leather which is tanned by slower methods. 
.... If upper leather and calf skins are to be sold 
by the pound (waiving the question of quality, especially 
toughness), then it is evident that these light tannages 
cannot be afforded. But if sold by measure, then a light 

T 



274 LEATHER MANUFACTURE. 

tannage is profitable to both tanner and consumer under 
proper circumstances." 

The above observations are introduced to solve the ques- 
tion whether a sole leather tanner who tans by the pound 
can afford to make heavy gains for his employer. One 
tanner makes 160 lbs. and another 170 lbs. of leather from 
100 lbs. of hides, "Are they," asks Mr. Schultz, "entitled 
to the same pay per pound ? Is the cost to each propor- 
tionate ? The argument on the one side is as follows : — 
It costs a certain sum to work in, handle, and finish a 
given lot of leather, whether of heavy or light tannage; 
the cost of the bark being alone considered, it cannot 
exceed, and most usually falls short of, the price received 
for tanning, even though the price be as low as six cents 
per pound. The sole leather problem is then, in fact, but 
the upper leather question over again, which would ask 
and determine the following : Can a customer afford to tan 
rough leather for less per pound than sole leather, less the 
finishing ? " He does not consider it an answer to say 
that they do tan it for less, or that small tan-yards, with- 
out much interest to pay, pursue the trade successfully, 
while the argument on the other side is that "heavy gains 
cannot be made with strong decoctions ; strong liquor can- 
not be obtained unless more or less waste is permitted — 
waste in the liquor itself, and more strength lost in leach- 
ing. Besides, the actual net added weight costs more than 
is received, which is calculated as follows : — 

Original weight of hide 100 lbs. 

Less hair, grease, fat, &c 15 „ 

Net gelatine and animal fibre 85 lbs. 

"Now, whether this product is raised to 160 lbs. or 
175 lbs. is a question of mere intrinsic cost of the pure 
tannin, icliich is capable of combining with the gelatine. 
In the one case 75 lbs. is required, and in the other 90 lbs. 
The cost of these respective factors made from bark at 
six dollars per cord would be (on the theory on which we 
are proceeding) fully eight cents per pound, since in both 
cases we start with the hide capital of 85 lbs. It may be 



COST OF AMERICAN TANNING. 275 

assumed that there is a discrepancy between the theoretical 
and practical percentage of tannin obtainable from bark. 
We know that 2,240 lbs. of hemlock bark will make only 
200 lbs. of leather. Chemists tell us, however, that there 
is 8 per cent, of tannin in this bark, consequently there 
is in this ton of bark 156 80-100 lbs., which, combined with 
85 lbs. of gelatine, should give 241 80-100 lbs. of leather 
[without reckoning the vegetable extractive ?] . What has 
become of this 71 lbs. of lost tannin? " 

May we not venture to suggest that while a consider- 
able proportion of the lost tannin is converted into gallic 
acid, a further portion is exhausted (especially when the 
liquors are made with hot water) by combining with the 
fibre of the bark — tanning it, in fact ? 

Mr. Schultz gives the following as the probable cost of 
each item in the production of hemlock leather : — 

Cost of bark (hemlock) per lb 3 cents. 

Cost of soaking, milling, sweating and beam work .... 1 cent. 

Yard work, including handling, laying away, &c ^ „ 

Finishing, including drying, rolling, &c | ,, 

Insurance, interest on tanning and bark | ,, 

Freight to and from the market 1 ,, 

Administration 1 

Total 7 cents. 



CHAPTER XXIV. 
MANUFACTURE OF LIGHT LEATHERS. 

Eussia Leather. — Count Kartstoff's Description of Russia Leather Manu- 
facture. — Smoking Skins. — Another Method of Preparing Russia 
Leather. — Black Russia Leather. — Yults Russia Leather. — Morocco 
Leather. — Sumao Tanning. — Imitation Morocco Leather. — Skiver. — 
Cordovan Leather. — Roan. — Hungary Leather. — Wallachia Leather. 
— Barley Dressing — Morfit's Remarks on White Dressing. — Bed 
Dressing. — Bran Dressing.— Enamelled Leather. 

Russia Leather. — The peculiar characteristics of this 
famous leather have won for it almost universal admi- 
ration. Its agreeable perfume, which, like the Tonquin 
bean, it communicates to other objects placed in contact 
with it ; its resistance to damp, which fails to produce 
that mouldiness or vegetable growth to which most 
leathers are subject under such conditions ; and the well- 
known fact that insects are repelled even by its odour, have 
combined to maintain the popularity of this agreeable 
leather. Although it is generally understood that the 
true secret of its manufacture has been jealously guarded 
by those whose interest it is to keep it from the public, the 
process, more or less accurate, has from time to time been 
made known by various writers. The process, as given 
by Ure,* is as follows : — 

" The skins are freed from the hair or fleece by 
steeping in an ash ley too weak to act upon the animal 
fibres. They are then rinsed, fulled for a longer or 
shorter time, according to their nature, and fermented 
in a proper steep, after having been washed in hot 

* " Dictionary of Arts, Manufactures," &c. 



LIGHT LEA TITERS. 277 

water. They are taken out at the end of a week ; but 
they may be steeped a second time, if deemed necessary, 
to open their pores. They are now cleaned by working 
them at the horse [or beam] on both flesh and grain sides. 
A paste is next composed, for 200 skins, of 38 lbs. of 
rye- flour, which is set to ferment with leaven. This 
dough is worked up with a sufficient quantity of water to 
form a bath for the skins, in which they are soaked for 
forty- eight hours ; they are then transferred to small 
tubs, where they remain during fifteen days, after which 
they are washed at the river. These operations serve to 
prepare the skins for absorbing the astringent juices with 
uniformity. A decoctiort of willow-bark (Salix cinerea 
and S. caprea) being made, the skins are immersed in the 
boiler whenever the temperature of the liquor is suffi- 
ciently lowered not to injure the animal fibres, and 
handled and pressed for half-an-hour. The manipulation 
is repeated twice daily during the period of a week. The 
tanning infusion is then renewed, and applied to the 
same skins for another week, after which, being exposed 
to the air to dry, they are ready for being dyed, and then 
curried with the empyreumatic oil of the bark of the 
birch-tree. To this substance the Russia leather owes its 
peculiarities. The skins imbibe this oil most equally 
before they are fully dry. Care must be taken not to 
apply too much of it, for fear of its passing through and 
staining the grain side of the leather." The red colour 
of Russia leather is supposed to be produced by Saunders- 
wood or Brazil-wood. 

Count Xartstoff's Description of Russia Leather 
Manufacture. — In a memoir published by Count Karts- 
toff, the following description of Russia leather tanning is 
given : — " The dried skins are softened by soaking in 
water for five or six days in summer and ten or twelve 
days in winter, and, after being well cleaned, are deprived 
of hair by steeping in milk of lime — 185 lbs. being 
mixed with water in a vat eight feet in diameter and seven 
feet eight inches high. The skins are frequently ex- 
amined, and when the epidermis and hairs give readily, 



278 LEATHER MANUFACTURE. 

they are carefully unhaired upon the beam and then 
fleshed. Stout hides are not limed, but exposed in a 
sweating-room, piled upon each other, and sprinkled with 
salt to prevent decomposition ; bran baths are used for 
the same purpose for thin and delicate skins. The skins, 
after being limed, are well soaked, washed, beaten out 
with the feet, and rinsed in warm water until the last 
portions of the lime have been removed from them ; they 
are then raised by steeping for forty-eight hours or more 
in a vat of the above dimensions, containing a fermented 
mixture of warm water with 1,100 lbs. of ryemeal, or 
450 lbs. of oatmeal, 6 lbs. of salt, and a sufficient quantity 
of leaven. Being thus prej)ared for tanning, they are 
steeped for a time in a weak infusion of oak or willow 
bark, the latter being preferred, and are then stratified in 
a vat with layers of coarse bark, the vat being filled 
up with the tanning infusion first used, and its contents 
being pressed down with planks, heavily weighted with 
stones. 

" The skins are left in this vat from fifteen to twenty- 
eight days, after which they are removed and again 
stratified with fresh bark. This operation is repeated 
from three to six times, according to the nature and 
quality of the skins, the thinnest kinds only requiring 
two changes. The stiffness acquired by the leather in 
tanning is then corrected by soaking them for a day or 
two in a paste composed of — for every 150 skins of 
ordinary size — 130 lbs. of oatmeal and 9 lbs. of salt, 
mixed with warm water. The leather is then well 
washed, rinsed, and drained, and, while in a partially 
moist state, is placed upon a large table, flesh side up, and 
coated with oil. This is composed of a mixture of the oil 
obtained from sea-calves (which abound in the Caspian 
Sea) and of the pure oil or tar of birch-bark in varied 
proportions, according to the nature and quality of the 
leather, one part of the latter to two parts of the former 
being generally used. The workman spreads the mix- 
ture with his hand evenly and uniformly over the surface, 
and the perfection of this operation depends upon tho 



LIGHT LEATHERS. 279 

skill with which it is done. About nine ounces of 
oil are applied to each skin of medium size. "When 
oiled, the leather is then stretched out upon cords in an 
open shed until perfectly dry, and in the winter season 
is exposed to the cold air, by which its appearance is much 
improved." 

Smoking Skins. — The Baskirs and Kerguises pre- 
pare their skins by smoking in lieu of tanning them. 
They first stretch them out, in their green state, between 
stakes fixed in the ground, and then remove the hair by 
scraping with a broken sickle fixed in a wooden handle. 
They then dig a pit in the ground, proportioned in size 
to the number of skins to be operated upon, and suspend 
them across parallel cords which are attached to its edges. 
A round hole is then dug five feet from the edge of 
the pit, and is connected with it by a subterranean gutter. 
The skins are hung upon the cords, the pit is covered 
over, and a fire of dry rotten wood is lighted in the small 
hole, the top of which is then closed. The smoke then 
passes through the connecting gutter into the pit, and the 
skins are kept exposed to its action for two or three 
weeks, at the end of which time they are found to have 
acquired properties similar to those of leather, and, above 
all, a degree of impermeability which does not exist in 
that which is tanned.* 

Another Method of Preparing Russia Leather. — 
This method, described by Yenables, is carried out as 
follows : — The whitest and most perfect skins being 
selected, are first soaked in water, then scraped upon the 
beam, fulled, worked with the pommel, and then oiled 
upon the hair side with pure fish-oil, and upon the flesh 
side with a mixture of oil and train-oil scourings. When 
dry they are again pommeled, washed over upon the hair 
side with a solution of alum, and then pressed under the 
cylinder. This cylinder, by which the diamond- shaped 
grain is given to Russia leather, is made of steel ; it is 

* It is more than probable that this primitive method of curing sMna 
was practised in the earliest ages, many centuries before the tanning pro- 
perties of plants were known. — A. W. 



28o LEATHER MANUFACTURE. 

about twelve and a half inches long and three inches in 
diameter, and is covered with a number of close parallel 
threads or grooves, like those of a screw, but cut perpen- 
dicular to its axis, and not spirally. The cylinder is 
filled with stones, and is moved in two directions upon a 
wooden bench or support by means of a cord passing 
round a wooden roller with a handle. This cord passes 
also over two cylinders attached to the floor and a fourth 
one upon the edge of the bench. The cylinder having the 
handle upon its axle is divided into two different parts, 
over which the two extremities of the cord pass in dif- 
ferent directions, so that two opposite movements can be 
given to the cylinder by one handle. 

The cylinder is sustained and directed by iron bars 
placed along the bench upon which it rolls. The skin 
which is to be grained is placed below it lengthwise upon 
the bench, and longitudinal grooves are pressed upon its 
surface by the track of the cylinder. The skin is then 
removed, and again placed upon the bench, either cross- 
wise or at an angle, according as it is intended to give it 
a square or a diamond-shaped grain. When properly 
grained, a second soak of alum-water is applied, and when 
nearly dry the Russian oil is spread over the grain side, 
and the red or black colour is given. The skin is then 
repeatedly exposed for a short time to the direct rays of 
a hot sun, until the colour has sufficiently penetrated its 
substance, when it is fulled, pommeled, sleeked with the 
round knife, upon the beam, and finally, well rubbed 
upon the hair side with a hard brush. The chief charac- 
teristic of the preparation of Russia leather is its impreg- 
nation with the birch-bark oil, the mode of preparing 
which is still, in a measure, kept secret. In order that 
the oil should penetrate the leather properly, the latter 
must not be either too moist or too dry, but should contain 
just sufficient water to enable the oil to spread equally 
over the surface, and be absorbed in proportion as the 
moisture gradually evaporates. Thus prepared, the leather 
retains the characteristic odour for a long time. Great 
care should be taken not to apply an excess of the oil. 



LIGHT LEATHERS. 281 

From 12 ozs. to 1 lb. generally suffice for fully impreg- 
nating a large cow-skin. In the case of leather not dyed, 
or of Morocco to which it may be desired to impart the 
odour, only a very small portion should be applied to the 
flesh side. The composition of the red colour with which 
Russia leather is commonly stained has not been accu- 
rately ascertained. It usually contains Brazil-wood, alum, 
and some other ingredients. It is not very durable,* and 
does not resist the action of boiling water or of potassa, 
though it generally remains unaltered in the air. Other 
d} T es of better quality are sometimes used, which enhance 
the price of the leather. 

Black Russia Leather is prepared in the same way 
as the other, and is stained by repeated applications of 
the acetate of .iron. 

Yufts, or Youfts Russia Leather. — Wagner describes 
the method of preparing this leather, the name of which 
is derived from the Russian word yufte, signifying a pair, 
because, as it is supposed, the hides are sewn together in 
pairs previous to the process of tanning. The hides 
usually prepared for leather in Russia are those of young 
cattle ; sometimes, however, the hides of horses and skins 
of sheep, goats, and calves are employed. The operations 
for preparing yufts are — 1. Cleaning of the hides with 
lime as usual. 2. Swelling or raising in a bath of sour 
wheat liquor, exhausted tan liquor, or mixture of dog's 
dung and. water. 3. Tanning with, various kinds of 
willows, fir and birch bark being also used. The pelts are 
first treated for some days in partly exhausted bark, and 
are next put into tanning tanks, along with bark, or 
sometimes into a warm infusion of the tanning materials. 
The tanning occupies from five to six weeks. 4. The 
tanned hides are placed on the planing block to drain, 
and are next impregnated with oil of birch. The oil is 
rubbed into the hides on the flesh side, and when 
thoroughly impregnated the hides are stretched until 

* In some specimens of Kussia leather binding in the Patent Office 
Library, London, not only has the colour faded, but the leather appears 
to be undergoing a process of decay. — Ed. Fifth Edition. 



282 LEATHER MANUFACTURE. 

they become soft and supple ; they are next rubbed on the 
grain side with a solution of alum, and then grained and 
dried. The dry hides are dyed in pairs, sewn together in 
the form of a bag, into which the dye material is poured. 
When a red colour is desired, the dye is prepared from 
sandal-wood, with the addition of potash or soda. By 
more recent methods, the hides are dyed by being 
brushed over five or six times with the dyeing material. 
After dyeing, the leather is dressed in the usual way. 

Oil of Birch. — The oil of birch employed in the pre- 
paration of Russia leather is obtained by dry distillation. . 
The whitish membranous epidermis of the birch, stripped 
of its woody matter, is placed in a copper still, to which 
is connected a pipe for conducting the volatile products to 
a receiver containing cold water. About 60 per cent, of 
the weight of the bark is in this way obtained in the 
form of a crude oil. 

Chevreul investigated the chemical nature of the oil of 
birch, and found that its odoriferous property is due to 
a peculiar compound, to which he has given the name of 
betuline from betula, the birch-tree. 

Morocco Leather. — Not less famous than the leather 
just noticed is that known as Morocco leather. Unlike 
the former, however, this kind of leather is very exten- 
sively manufactured both in this country and on the Con- 
tinent, and forms an important branch of industry with 
the manufacturers of light and fancy leathers. True 
Morocco leather is goat skin tanned, and dyed on the grain 
side. The skins of sheep, however, are extensively em- 
ployed for conversion into a cheaper variety of this 
leather, and are, after tanning, dyed in a great number of 
different colours. 

Morocco leather prepared from goat skins is exten- 
sively used for carriage-linings, chair-covers, for superior 
bookbinding, pocketbooks, purses, and many other useful 
purposes. This leather is remarkable for its glossy, 
wrinkled, and fibrous appearance. The goat skins from 
which Morocco leather is manufactured in England are 
largely imported from Switzerland, the East Indies, Cape 



LIGHT LEATHERS. 283 

of Good Hope, Memel, Mogadore, Asia Minor, Germany, 
and other parts of the world. The skins vary con- 
siderably in size and thickness, as also in quality, and are 
imported with the hair on. 

An important feature in the preparation of Morocco 
leather is the tanning process, which is effected with 
sumac in a very peculiar way, as will be explained 
further on. The goat skins are first soaked, or drenched, 
in water for several days, to soften them, and are next 
broken — that is scraped or rubbed on the beam, on the 
flesh side, to further soften them and to remove flesh}^ 
matters which would interfere with the action of the lime 
liquor to which they are afterwards subjected. They are 
then placed in old lime liquor for two or three days, after 
which they are handled or " drawn," by removing them 
from the pits by means of small tongs (Fig. 48), and 



Fig. 48. 

placing them in a heap for a few hours. They are next 
transferred to a " middling " lime liquor for several days, 
being frequently drawn as before, and the skins are finally 
placed in pits containing strong lime liquor, in which 
they are allowed to remain with frequent handling or 
" drawing," until the epidermis readily yields to the 
touch. The liming generally occupies from about ten to 
fourteen days in summer, but in winter a longer period 
is required. 

Unhairing and Fleshing. — The goat skins, when ready 
for unhairing and fleshing, are removed to the jlcshing 
shop, or beam house, in which a series of teams, placed at 
equal distances from each other, are arranged opposite the 
windows of the apartment, whereby the workmen are 
enabled to perform their operations in a good light. Each 
goat skin is laid smoothly on the beam, with the hair side 
upward, and the beam man, standing behind the beam, 
scrapes the hair from the pelt by means of the two-handled 
unhairing knife. Fig. 49 illustrates the operation. After 



284 LEATHER MANUFACTURE. 

being unhaired the goat skins are again steeped in lime 
liquor for two or three days, after which they are 
fleshed on the beam. The lengthened sfceepings in the 
lime-pits naturally cause the lime to enter into the pores 
of the skin, and therefore its entire removal is the next 
most important step, so that the tanning principle of the 
sumac may fully enter into the fibrous structure of the 
pelt. For this purpose a mixture composed of dogs' 
dung and water is employed. This mixture, called the 
pure, is of an alkaline nature, and has the effect of convert- 




Ffc. 49. 



ing the lime within the pores of the skins into soluble salts, 
which eventually become removed by washing and the 
mechanical processes of scraping or scudding. A great 
many attempts have been made to provide a less disagree- 
able substitute for the excrement of dogs, but the fact 
that this material is still extensively used, especially in 
England, would indicate that as yet no efficient substitute 
has been found. 

Scudding. — After remaining in the pure for some time, 
the skins are removed, and after being steeped they are 



LIGHT LEATHERS. 2S5 

forcibly scraped, or scudded, as it is termed, with a blunt 
two-bandied knife, botb on the grain and flesh side, by 
which the remaining lime and albuminous matters are 
forced out of the pelt. They are then again steeped for a 
short time, and the effect of the various operations to which 
they have been submitted is that the pores of the skins are 
opened and free from all such matters as would prevent the 
proper absorption of the tanning principle. 

Sumac Tanning. — The peculiar nature of this tanning 
material, which is of a yellow colour, renders it necessary 
to apply it in such a way that its action upon the pelts 
shall be perfectly uniform, a result which would not be at- 
tained if the skins were immersed in an infusion of the 
material in the same way as in ordinary bark tanning. In 
order, therefore, to insure perfect uniformity in the action 
of the sumac tannin, the following system is adopted : — 
The pelts, after passing through the various operations 
above described, are transferred to an apartment in which 
they are sewn up into bags by women — each skin forming 
a bag — with the grain side outward, a small opening at 
the hinder part only being left for the introduction of a 
funnel. At Messrs. Bevingtons' Bermondsey works these 
bags are now made by the sewing-machine. When the 
bags are made they are thrown into a vessel of water and 
examined to ascertain if they are properly sewn and free 
from holes. They are next taken to the sumac tub, which 
is a large shallow vessel about fifteen feet in diameter, 
and which is filled with hot water containing a little 
sumac. Close to this tub is a smaller vessel containing 
a strong solution of sumac. 

The method of filling the bags with the stronger 
solution is as follows, and is performed by two men and a 
boy. Taking their places by the side of the smaller tub, 
the lad takes one of the bags and inserts the neck of a 
funnel in its opening, when one of the workmen nearly 
fills the bag through the funnel with the strong sumac 
solution by means of a ladle (Fig. 50). The second man 
then takes the bag from the funnel and inflates it with 
his breath, after which he closes the aperture by tying it 



286 



LEATHER MANUFACTURE. 



with a piece of string. The bag, in its distended condition, 
is perfectly free from wrinkles, the presence of which 
would interfere with the uniform action of the tanning 
material, and its contained air enables the bag to float in 
the liquor of the larger vessel. All the bags, as they 
are filled, are thrown into this larger tub, in which they 
float like bladders, and they are kept in constant motion 
for about three hours in this way : two men, one on each 




Fig. 50. 

side of the tub, take each a wooden paddle, which they 
work to and fro in the solution, causing the floating bags 
to roll gently over and over, by which the sumac solution 
in the bags becomes uniformly diffused over their inner 
surface, and eventually permeates the entire substance of 
the skin ; the absorption of the tanning principle is greatly 
aided by the warm temperature of the solution in which 
the skins are floated. The goat skins being very thin, are 
effectually tanned by this method in a few hours. In 
Fig. 50 a workman is also seen in the act of moving the 
floating bags about in the sumac tub. During the 
process of sumaching the bags are removed once from 
the tub, and are piled up in a heap upon a rack near 
the tub, and by means of their own weight the sumac 
solution is forced through the pores of the skins. After 



LIGHT LEATHERS. 287 

this they are subjected to another sumaching operation, 
and are then once more piled up in a heap to acquire 
the necessary pressing, by which time the operation is 
complete. 

The bags are now removed to another apartment, where 
the stitching is undone and the sediment which remains 
from the sumac is removed from the interior. This refuse 
generally consists partly of yellowish sandy matter with 
which the material had been adulterated before importation 
from Sicily. This waste, being of no farther use in tan- 
ning, is sold as manure. The tanned pelts are next 
thoroughly washed, and are then laid out smoothly upon 
a sloping board ; they are next " struck," as it is termed 
— that is, scraped and rubbed until they are perfectly 
smooth. They are then hung up in a loft to dry. When 
dried they are said to be in the crust, and present a some- 
what shrivelled and irregular appearance. To render 
them smooth, preparatory to dyeing them, the skins are 
first wetted, and then once more struck, or smoothed, as 
before, after which they are ready for the dyeing-house. 
The process of dyeing Morocco and other leathers is given 
in another chapter. 

Imitation Morocco Leather. — This is chiefly prepared 
from sheep and calf skins, and is extensively used for bags, 
bookbinding, chair-covers, and many other useful pur- 
poses, and as now manufactured bears a close resemblance 
to the true Morocco. The sheep skins, before they come 
into the tanner's possession, are deprived of their wool by 
a class of manufacturers called fellmongers, who receive the 
skins in the condition in which they leave the slaughter- 
houses. After the skins are fellmongered, the wool is dis- 
posed of to the ivoolstapler, and the fells, as they are 
termed, to the tanner and manufacturers of parchment. 

The unwoolled sheep skins or fells are treated much in 
the same way as goat skins ; since the skin of the sheep, 
however, is naturally of a more greasy and oily nature 
than that of the goat, it requires very careful treatment to 
remove these greasy matters before being submitted to the 
operation of sumac tanning ; the skins are therefore first 



288 LEATHER MANUFACTURE. 

submitted to powerful hydraulic pressure, by which the 
greasy matters are forced out from the pores of the skin. 
They are then subjected to the same treatment as goat 
skins, excepting that they are tanned by immersion in 
sumac liquor instead of being sewn up into the form of 
bags, as in the case of goat skins. 

Skiver. — When sheep skins are split by means of the 
splitting machine, the grain splits, as they are called, are 
converted into a thin variety of leather called skiver, which 
is much used for common bookbinding, pocket-books, hat 
linings, and other purposes requiring a cheap but strong 
leather. The flesh splits, as we have before said, are em- 
ployed for making inferior kinds of chamois or oiled 
leather. The thin skivers, being more readily acted 
upon by the sumac tan than goat skins, are not sewn up 
into bags, but are immersed in the sumac tub in an open 
state, and are tanned in a very short time. 

Cordovan Leather. — This leather derives its name from 
the city of Cordova, in Spain, where it is supposed to have 
been originally prepared by the Moors. It has a very fine 
and beautiful grain, and is dyed in every variety of shade 
and colour. The finest qualities are imported from the 
Levant, but those of Spain, France, Hungary, and Ger- 
many are also highly esteemed. The skins employed in 
the manufacture of Cordovan leather are those of the goat 
and dog, and sometimes also hog skins are used, but the 
leather prepared from goat skins is preferred. The skins 
after being cleaned and drenched in water, are limed, after 
which they are again steeped in water for eight to fifteen 
days, during which period they are repeatedly worked by 
treading upon them with the feet. At the end of a fort- 
night they are steeped in a lukewarm mixture of dogs' 
dung and water, next into a bran bath, and after removal 
from the latter, the skins are then stretched, pressed 
between two boards, and rubbed with common salt. They 
are next immersed in a bath prepared from figs and water. 
Only skins that are to be coloured black are dyed after 
being tanned. Black leather is tanned in liquor of extract 
of oak-bark ; that of lighter colour in ooze prepared from 



LIGHT LEATHERS. 289 

extracts of sumac and nut-galls. When the operation 
of tanning is complete the leather is withdrawn, taking 
with it as little liquor as possible, and spread in the 
shade, when it must be rubbed on the bloom with oil of 
sesame before the sides have become perfectly dry. 
After the oil is laid on, drying in the shade is allowed 
to be completed, when the skins are folded on the flesh 
side. When it is desired to give the Cordovan a rough 
appearance, the surface may be rubbed with a blunt knife 
immediately after spreading. In many parts of Russia 
wormwood (Artemisia absinthium) is employed to fix the 
colour in the leather. If, for example, it is desired to dye 
the leather black, a decoction of wormwood is mixed with 
powdered cochineal, and alum is then added. 

In the island of Cyprus, Cordovans are dyed red in the 
following manner : — The skins, generally about fifty at a 
time, are placed in a fig bath ; they are then passed into 
a strong solution of alum heated to about the temperature 
of new milk ; they are afterwards hung upon poles to drain, 
and are next stretched to expel as much moisture as pos- 
sible ; finally, the skins are placed on a table, and after 
being uniformly stretched, the red colour is applied with a 
cotton rag. The colouring-matter is prepared by taking 
ground cochineal and boiling it in soft water in a well- 
tinned kettle, and during the ebullition 5 ozs. of powdered 
alum are added for every 5 ozs. of cochineal, and the liquor 
boils until reduced to one-sixth or one-eighth by evapora- 
tion, when it is passed through a filter. The skins are 
coated four or five times with this preparation, and after 
being placed in the tanning liquor are submitted to the 
operations of dressing. 

In Hungary and Transylvania, where the manufacturers 
of Cordovan produce goods which are highly esteemed, the 
red colour is laid on in a different manner. When the skins 
have been properly prepared, they are fastened together in 
pairs, in the form of bags, with the sides to be coloured 
inside. Into an opening in this bag the warm colouring- 
matter is poured, and in order to insure uniformity of its 
action the bag is occasionally agitated by being rolled about. 

U 



290 LEATHER MANUFACTURE. 

Koan. — This leather is prepared from sheep skins, much 
in the same way as Morocco, being tanned with sumac, 
but in the after processes of currying it is not grained like 
the latter. 

Hungary Leather. — The mode of preparing this leather, 
which is peculiar, consists in impregnating strong hides 
with alum, common salt, and tallow, by a quick process, 
which is generally complete in about two months. The 
process is thus given by Ure : — " The workshop is divided 
into two parts. 1. A shed on the side of a stream, fur- 
nished with wooden horses, fleshing-knives, and other 
small tools. In one corner is a furnace with a boiler for 
dissolving the alum, a vat for immersing the hides in the 
solution, and several tubs. 2. A chamber 6 feet high by 
15 feet square, capable of being made very tight for pre- 
serving the heat. In one corner is a copper boiler, of 
sufficient size to contain 170 lbs. of tallow. In the middle 
of the stove is a square stone slab, upon which an iron 
grate is placed about a yard square. This is covered with 
charcoal. At each side of the stove are large tables, which 
occupy its whole length, and on which the leather is spread 
to receive the grease. The upper part below the ceiling is 
filled with poles for hanging the leather upon to be heated. 
The door is made to shut perfectly close. The first opera- 
tions are analogous to those of tanning and tawing, the 
skins being washed, cut in halves, shaved, and steeped for 
twenty-four hours in the river. They are cleaned with 
5 or 6 lbs. of alum and 3 \ lbs. of salt for a piece of hide 
which weighs 70 to 80 lbs. The common salt softens the 
effect of the alum, attracts moisture from the air, and pre- 
serves the suppleness of the skin. When the alum and salt 
are dissolved, hot water is poured upon the hides placed in 
a vat, and they are trampled upon by a workman walking 
repeatedly from one end of the vat to the other. They 
are then transferred into a similar vat containing hot 
water, and similarly trampled upon. They are next steeped 
for eight days in alum-water. The same round of opera- 
tions is repeated a second time. 



LIGHT LEATHERS. 291 

" The skins are now dried either in the air or a stove- 
room, but before being quite dry they are doubled together, 
well stretched to take out the wrinkles, and piled up. When 
dry they are again trampled to open the pores, as well as to 
render the skins pliant, after which they are whitened by 
exposure to the sun. Tallow of inferior quality is employed 
for greasing the leather. With this view the piece is 
hung upon the poles in the close stove-room, then laid 
upon the table and besmeared with the tallow melted till 
it begins to crumble. This piece is laid on another table, is 
there covered with a second similarly greased, and so forth. 
Three pounds of fat are commonly employed for one piece 
of leather. When the thirty strips, or fifteen hides, passed 
through the grease in one operation are completed, two 
workmen take the first piece in their hands, and stretch it 
over the burning charcoal on the grate for a minute, with 
the flesh side to the fire. The rest are passed over the 
flame in like manner. After flaming, the pieces are suc- 
cessively laid on an inclined table exposed to the fire, 
where they are covered with a cloth. They are finally 
slung upon poles in the air to dry ; if the weather be 
warm, they are suspended only during the night, so as 
to favour the hardening of the grease. Instead of the 
alum bath, ]VL Curaudau has employed with advantage a 
steep of dilute sulphuric acid." 

Wallachia Leather. — The following; is an abridgment 
of Morfit's description of the Wallachian method. This 
leather is prepared by barley dressings in a simple warm 
vat, and the skins are unhaired by a fermentative process 
instead of the usual liming. Dry hides, after being 
softened in water, are first trampled upon and then 
worked on the flesh side upon the beam, to render them 
pliant ; they are next steeped in water for a short time, 
and then hung up to drain. They are now examined, to 
ascertain if the hair comes away easily ; for in hot climates 
during the summer-time this is effected without any other 
process of depilation. When fresh skins are employed, 
fermentation is resorted to for loosening the hair. After 



2 9 2 LEATHER MANUFACTURE. 

removing the tail, horns, and ears, the skins are salted 
without being soaked. The salting consists in sprinkling 
each large hide with four to six pounds of salt, alum, and 
saltpetre ; the hides are then folded and stacked in a heap, 
which is then covered with litter. After a short time the 
hides become heated, and they are turned over once or 
twice a day, so as to render the fermentative process uniform 
throughout. When it is found that the hair yields to the 
touch, the operation of unhairing is promptly performed, 
since if the skins were allowed to remain for too long a 
period under the influence of the fermenting process, the 
pelt would suffer decomposition and consequent injury. 
In cases where it is inconvenient to unhair the skins 
"immediately they are in the proper condition, they are 
steeped in water for one or two days, but not longer; 
otherwise putrefaction would ensue. 

Raising. — When the depilation is effected, the pelts are 
treated in a bath composed as follows : — For seven skins, 
each averaging 80 lbs., 20 lbs. of flour are made into leaven, 
which is worked up into a pasty condition with water ; to 
this a gill and a half of vinegar is added to promote the 
acetous fermentation. The preparation of the leaven 
occupies about twenty-four hours, and the vessel in which 
it is placed must be kept in a warm place, well covered 
up for three or four days. The tub for seven skins is 
about five and a quarter feet across, and three and a quarter 
feet high, and must be perfectly clean and free from any 
matter which would check the progress of the fermenta- 
tion. The tub is filled with water, with which the leaven 
is well incorporated by stirring. Six or seven bucket- 
fuls of the liquor are then put into a kettle and boiled, and 
a portion of this used to make a uniform paste with ground 
barley, and this is afterwards thinned with cold water 
until it has a syrupy consistence. This compound is next 
boiled until it froths, and is kept constantly stirred with a 
wooden paddle. When the compound has frothed up 
three times, it is ladled into the tub to be employed for 
the dressing, and cooled down by stirring continually in 
one direction, until the hand can readily bear its tern- 



LIGHT LEATHERS. 293 

perature. Six pounds of salt are then added and well 
stirred in, and the tub is then covered up and allowed 
to repose for a fortnight to sour, the mixture being 
stirred twice a day during this time, and the vessel being 
immediately covered after each stirring. 

The skins being removed from the rinsing water, are 
strung in threes with a cord and thrown into the tub, 
where they are allowed to remain for four or five days, 
being, however, drawn twice daily and left to drain for a 
minute, and then returned to the tub. "When the skins 
are sufficiently soft, they are next fleshed and unh aired, 
and are then rinsed in clean water, after which they are 
hung up to drain for twenty-four hours. While the above 
operations are in progress, a second leaven is prepared 
from 16 lbs. of meal, and fermented in the same 
way as the former. The clear sour liquor of the first 
dressing is now transferred to a second tub, in which the 
dressing is completed. Six or seven bucketfuls of the 
clear sour liquor are taken from each tub, and a portion 
stirred up with 50 lbs. of ground barley — about 8 lbs. for 
each skin. The remaining hot water is then added 
gradually, and the whole gently boiled and added to the 
new dressings and well stirred in. One or two bucket- 
fuls are taken out and heated to near the boiling-point. 
Another leaven, prepared from 8 lbs. of meal, is then 
diffused through the tubs, and from 4 to 6 lbs. of salt 
added to each, with stirring. The process may be sim- 
plified by making one steep instead of two, by using at 
first 30 lbs. of leaven, 120 lbs. of barley, and 10 lbs. of 
salt for each dressing of six hides. 

Relative to barley dressing, Morfit says, "It must be 
observed that, by the ordinary process, the tanners use at 
one time, in their first new dressings, just twice the 
quantity of barley that would be employed here [Wal~ 
lachia], and, moreover, when their first new dressing is 
not sufficient, they are obliged to make a second, which 
renders the process more tedious and expensive than that 
of Wallachia. It is also necessary to say that, on the 
addition of salt, the dressing must always be well stirred, 



294 LEATHER MANUFACTURE. 

and two or three bucketfuls of the liquor drawn out from 
each and kept warm, to be poured into the vat in order 
to maintain the temperature. Several other bucketfuls are 
also taken out and poured into a reserve tub, so that no 
more liquor may remain in each dressing than is sufficient 
to cover the skins subjected to its action. Many tanners 
believe that it is better to make the whole composition 
at once, for independently of loss of time and fuel, the 
complement made with the new quantity of barley may 
retard the progress of fermentation, and the liquor must 
be heated to a temperature which would be injurious to 
the skins." 

There are several methods of preparing the composition 
for barley dressing : 1, from barley or rye meal, without 
leaven, prepared overnight with boiling water ; 2, from 
equal parts of barleymeal and leaven, thinned with water, 
and heated to boiling just previous to putting in the skins ; 
3, from wheat bran, in the proportion of half a bushel per 
hide, weakened with hot water, and after a day's fermen- 
tation mixed with 1 lb. of salt for each skin ; 4, from 
leaven of barley or rye, in the proportion of from 6 to 8 lbs. 
of meal per hide. When the leaven rises, it must be 
thinned with water at 86° Fahr., and the salt added just 
before the skins are immersed. 

Barley Dressing. — When the fermentation is well 
established, which is indicated by the liquor becoming 
sour, the dressings, as they are called, are ready for the 
skins, which are taken from the hangers and passed 
through the liquor several times, so as to equalise the tem- 
perature. They are now left upon the cover of the tub for 
a few minutes to drain ; the liquor is then stirred, and 
the skins returned to the tubs, which are then covered, 
and the temperature of the dressings is kept up by 
additions of the hot reserve liquors. In a quarter of an 
hour the skins are again drawn out and left to drain as 
before, after which they are replaced in the tub, and half 
an hour after are again withdrawn and left to drain for 
a quarter of an hour. They are then replaced in the tub, 
again removed, and drained for twenty minutes. In the 



LIGHT LEATHERS. 295 

fifth, dipping the skins are left in the bath for an hour, 
after which they are drained for half an hour, and then 
returned to the tub. These operations are repeated in all 
about eight times. If, on the following day, the hides are 
not sufficiently raised, they are dipped several times more 
until the required condition is attained. The heat of the 
dressings must be kept at from 105° to 120° Fahr. by 
additions of hot liquor. 

Morfit's Remarks on White Dressing. — " Experience 
has proved that the action of the white dressing is com- 
pleted in about thirty-six hours ; the acetic fermentation 
which ^s established so expands the hides that they become 
as thick as the leather into which they are about to be con- 
verted. Care must be taken not to leave them any longer 
in the liquor after this point has been attained, for it in- 
jures the leather, a result which also takes place if the 
liquor is too strong. After the removal of the skins from 
the liquor, the latter must be reserved for new dressing, 
for which purpose it must be heated with a complement 
somewhat stronger than the first. This acid liquor greatly 
facilitates the fermentation of the new composition, which 
sours rapidly. In this manner, when the white dressings 
are once in train, they may be kept at one-half the expense 
of flour, time, and money." 

When removed from the dressings, the hides are left to 
drain on the cover, and when cooled are soaked in water 
for a few moments to remove the viscid coating derived 
from the barley, and they are then again drained. 

Red Dressing. — The skins are now subjected to what 
is termed the red dressing, preparatory to their being 
placed in the tan-vats. This dressing is made by putting 
about 40 lbs. of crushed bark, mixed with water, into a 
tub. Into this the hides are then placed, and allowed 
to remain for several hours, when they are taken out and 
drained for a few minutes. A few hours after further 
immersion this operation is repeated, but previous to 
returning the skins to the vat the last time an addition 
of 40 lbs. more crushed bark is made, and this is well 
stirred in. On the mornings of the second and third 



296 LEATHER MANUFACTURE. 

days, 24 lbs. of bark are added, the skins taken out 
thrice daily, half an hour being allowed for each drain- 
ing. On the fourth day the skins are drained morning 
and evening, forty-five minutes being allowed each time. 
On the morning of the fifth day the hides are taken out, 
and while draining the liquor is well stirred. The hides 
are then put back, hair side upward, and a few handfuls 
of crushed bark thrown in between each skin, and on the 
top of the last one, which should have its flesh side upward, 
a layer of bark is spread. The skins are now left for eight 
to ten days, then removed, rinsed in clean water, and put 
into the tan- vats. 

Bran Dressing. — Some tanners contend that the red 
dressings may be omitted if the white dressings are made 
with bran. The unanimous opinion of many tanners 
whom we have consulted on the subject is in favour of red 
dressings. The bran dressings are prepared either hot or 
cold. In the first, the leaven is prepared from yeast, or 
made with 1 to \\ lbs. of wheat or rye flour per hide, and 
kept at a moderate temperature, which quickly sours. 
After the skins have been soaked and cleansed, they are 
lleshed and rinsed in water. They are then put into a 
bath composed of bran liquor as follows : A sufficient 
quantity of water for all the skins is boiled with bran, in 
the proportion of 7 or 8 lbs. for each skin ; the boiler 
is then covered, and when the liquor has sufficiently fer- 
mented, which is known by the bran rising to the sur- 
face, the liquor is transferred to a vat in which the skins 
were previously deposited. While the skins are getting 
warmed, another quantity of water is heated until it sim- 
mers, when to this is added the fermented liquor first pre- 
pared. The skins are then taken out of the vat, and the 
fresh mixture is poured in, with the addition of salt in the 
proportion of rather more than 1 lb. per skin, and the 
whole is well stirred. The skins are now placed in the 
vat, where they are allowed to remain for about six hours. 
They are then removed and drained for a short time, and a 
portion of reheated liquor put into the vat. The same 
operations are repeated every six hours during two days. 



LIGHT LEATHERS. 297 

When the hair is loosened it is removed in the usual way. 
after which the skins are fleshed and soaked in cold water 
for a quarter of an hour ; they are then returned to the 
vat, and allowed to remain until sufficiently raised. By 
reheating a portion of the liquor from time to time, and 
keeping the vessel covered, the raising will generally be 
effected by the end of three days. The skins are now 
rinsed and left in soak for some hours in fresh water, when 
they are ready for the subsequent tanning operations. — 
Morfit. 

Enamelled Leather. — This variety of leather, which 
for a long period was known under the title of "patent 
leather," is prepared from calf, seal, and other skins, with 
a varnish composed of drying oil, vegetable black, and 
Prussian blue. The skin is first stretched on a fiat board, 
and every trace of grease is then removed from the surface 
by means of a paste made with fuller's earth and water, 
which is afterwards thoroughly removed by rubbing. 
The skin is then ready to receive the first coat of varnish, 
which is composed of Prussian blue (that which contains 
some alumina) 5 ounces ; drying oil, 1 gallon. These 
being well mixed or ground together, are boiled to the 
consistence of "single size;" and when cold, a small 
quantity of vegetable black is added and ground up with 
the mixture. The first coat is given by pouring some of 
the varnish over the leather, and then spreading it over 
thinly with a kind of scraper until the entire surface is 
evenly coated. The leather is then placed in a drying 
stove, and when sufficiently set is placed aside to cool ; it 
is afterwards polished with finely-powdered pumice. A 
second coating is then given with the varnish, in which a 
little pure Prussian blue has previously been mixed, and 
the leather is again stoved and polished with pumice as 
before. For the third coat the varnish consists of a similar 
mixture, but the oil is boiled until it strings well, and a 
little more Prussian blue and vegetable black are added, 
the varnishing, stoving, and polishing being pursued as 
before. The last coat, or finish, is given with a varnish 
like the third, with the addition of | lb. of pure dark- 



298 LEATHER MANUFACTURE. 

coloured Prussian blue and \ lb. of pure vegetable black 
per gallon, and to this a little oil, copal, or amber varnish 
are sometimes added. The heat of the stove or oven is 
usually about 120° Fahr. for enamelled skins, as those of 
calf and seal intended for uppers, and 175° Fahr. to 180° 
Fahr. for stout " Japan leather." The exposure in the 
stove is commonly from six to ten hours. 



CHAPTER XXV. 

DYEING LEATHER. 

Dyeing Morocco Leather. — Dyeing with Aniline Colours. — Dyeing Kid 
Leather for Boots. — Bath Dyeing. — Dyeing on a Flat Surface. — 
Aniline Colours in Glove Dyeing. — Dyeing with Pure Aniline 
Colours. 

Dyeing Morocco Leather. — After the goat skins have 
been sumached, opened, and well washed, they are spread 
out upon a sloping board and struck out, that is scraped and 
rubbed out as smooth as possible, after which they are 
hung up in the loft to dry. When thoroughly dried they 
are in a hard and shrivelled condition, and are said to be 
" in the crust." To bring the skins to a proper condition 
to receive the dye, they are first softened or " seasoned " 
in water, after which they are struck out or smoothed 
again, when they are ready for dyeing. Since Morocco 
leather only requires to be coloured or dyed on one side, 
it is usual to lay two skins of the same size in close con- 
tact, flesh to flesh, before dyeing, so that the dye liquor 
may only penetrate one side of each skin. For red Mo- 
rocco, the skins are first mordanted either with a solu- 
tion of tin or with alum water, after which they are 
immersed in a bath prepared from cochineal, boiled in 
water, with a little alum or tartar added, the liquor 
being filtered through a linen cloth before use. After 
about half an hour the skins are withdrawn and then 
subjected to another immersion in the cochineal bath. 
They are then rinsed, drained, oiled on the grain side, 
and hung up to dry, after which they are transferred to 
the currier. 



3oo LEATHER MANUFACTURE. 

Black Dye is given by brushing over the grain side a 
red solution of acetate of iron. For blue, the cold indigo 
vat is used. Violet is produced by first dyeing a pale blue, 
and afterwards dipping in the red cochineal vat. For green, 
Saxon blue, followed by a yellow dye, produced by the 
chopped roots of barberry. Puce colour is produced by 
logwood, with a little alum added ; olive, by first passing 
the skins through a weak solution of copperas, and next 
through the decoction of barberry root containing a little 
Saxon blue. After dyeing, the skins are rinsed and 
drained, after which they are laid flat on a table, and 
smeared over with linseed oil on the grain side by means 
of a sponge, to render the surface glossy when curried, and 
also to prevent them from drying too rapidly and thus be- 
coming hard and flinty. 

Dyeing with Aniline Colours. — Since the introduction 
of the famous aniline or coal-tar dyes, many hues have 
been given to leathers which could not be produced with 
equal facility by means of the ordinary dye stuffs. The 
great brilliancy of the aniline dyes, and the readiness with 
which they combine with animal substances, render them 
most potent auxiliaries in the dyeing-room, and with ne- 
cessary care in their employment they are capable of pro- 
ducing a great variety of tones or shades of exquisite 
brilliancy. 

The Gerber Zeitung, to which the leather trades are in- 
debted for much valuable information, has recently contri- 
buted a series of memoirs upon dyeing leather with aniline 
colours, which cannot fail to prove highly serviceable to 
those who are engaged in this important branch of manu- 
facture. These papers having been reproduced in the 
Dyer and Calico Printer,* we are indebted to that useful 
journal for the following extracts : — 

Dyeing Kid Leather for Boots. — The subject is con- 
sidered in two main divisions, namely, the dyeing of 
leather for boots and for gloves. The leather used for the 
first-named purpose is usually that which is too imperfect 
for the manufacture of gloves. The first process is soften- 
* The Dyer and Calico Printer, February, March, and June, 1884. 



DYEING LEATHER. 301 

ing the skins in water. The dyeing is effected by two 
methods — plunging, or dyeing on the flat surface. In the 
latter case the skin is white on the flesh side. In the old 
process of dyeing with wood colours, it was considered 
necessary to adopt the plunging method for all delicate 
shades, but with aniline colours this is not necessary. 
With any dilute dye-wood decoctions it is impossible to 
produce on the skin by means of brushing a full and uni- 
form tone of colour, but with aniline colours it is quite 
possible to produce on a flat surface the most delicate 
shades obtainable by plunging. The skins must be 
stretched out on a flat surface to free them as much as 
possible from moisture. 

As mordants for the so-called kid leather dyeing the 
following acids are used : sulphuric, phosphoric, tartaric, 
oxalic, tannic, and acetic acids. Amongst the alkalies 
used as mordants are soda, potash, and ammonia. Acids 
must be used with all blue aniline colours, with most 
greens, as well as with many yellows and browns. Alka- 
lies are used with all red aniline dyes and with kindred 
shades. 

Bath Dyeing. — The modes of dyeing are, as we have 
said, bath dyeing and dyeing on a flat surface. The first 
is carried out by filtering a solution of the aniline colour 
made with hot water. A portion of this solution (of 5 to 
10 per cent, strength) is poured into lukewarm water in a 
vat, and the skins are placed singly in it, a workman tread- 
ing them down with his feet and keeping them in motion. 
When the colour has been taken up by the skins, they are 
removed and subjected to slight pressure, and more colour- 
ing matter added to the bath, the process being repeated 
till the skins have taken the desired shade. To determine 
what the colour of any particular stage will be when 
dried, a small piece is cut from a corner and put in a linen 
cloth which is repeatedly wrung, when the ultimate shade 
after drying and dressing will be seen with relative ac- 
curacy. The skins are now taken out and slightly pressed, 
the colouring liquor is poured off, except a small residue, 
to which yolks of eggs and salt are added ; the skins are 



302 LEATHER MANUFACTURE. 

then replaced and the previous treatment renewed. As 
this process gives a slightly yellowish tinge, this fact 
should be kept in view in dyeing the shade in the first 
instance. The skins are then spread out and allowed to 
drain, after which they are dried. 

To arrive at the desired shades, such as pink, eosine is 
taken for a yellowish tinge. 1. For pure pink, eosine 
two parts, phloxine one part. Pink with a bluish tinge, 
phloxine two parts, eosine one part. Phloxine for a dis- 
tinctly bluish tinge in a delicate shade. 2. Straw is pro- 
duced by the use of naphtholine yellow, and for specially 
strong shades some methanil yellow. 3. For cream, a 
very weak solution of naphtholine yellow. 4. Salmon is 
produced by mixing the latter colour and eosine in the 
following proportions : For the more reddish shades, 
eosine two parts, naphtholine yellow one part ; for more 
yellowish shades, eosine one part, naphtholine yellow one 
part. Buff, eosine and methanil yellow in equal propor- 
tions for the more reddish shades, and equal parts of 
phloxine and methanil yellow for a bluish tinge. For the 
above colours it is recommended to add some phos- 
phate of soda to the dyeing-bath, to facilitate the process 
and impart brilliancy to the colours. 

Dyeing on a Flat Surface is effected by first applying 
to the stretched- out skin a mordant with a medium soft 
brush. The colouring substance is then applied with a 
brush. After two applications the skin is drained so as 
to allow fresh colouring matter to be taken up. When 
the skin is sufficiently dyed the excess of colour is 
removed with water. Draining then follows, and the 
skin is hung up to dry. 

The following are some of the shades obtained by this 
method : — 1. Cream : Solution of naphtholine yellow in 
water one-sixteenth per cent. The skin is mordanted with a 
solution of phosphate of soda in water (proportion 1 : 100). 
Three brushes of the above weak solution of dye stuff are 
applied, the skin being drained after the second brushing. 
As a coating, a solution of dextrine in water mixed with 
phosphate of soda may be used : phosphate of soda one 



DYEING LEATHER. 303 

part, dextrine two parts, water 100. This coating can be 
used as a mordant, and produces a silky brilliancy which 
protects the colour from the influence of the air ; otherwise 
aniline colours fade, even without the action of light. 2. 
Straw : Naphtholine yellow one part, water 400 parts. 
Treat as before. 3. Golden yellow : Methanil yellow one 
part, water 100 parts. 4. Pink, with yelloxds'h tinge : A 
solution of eosine made with one-sixteenth' per cent, of 
eosine. 5. Pink, with bluish tinge : A solution of phloxine 
(one-sixteenth per cent.). 6. Pure pink: A mixture of 
the above solutions in equal proportions. 7. Cerise is ob- 
tained with a one per cent, solution of erythrosine, three 
or fourTmishes being used in the subsequent process. 8. 
Sky blue is obtained by means of water-blue D.N. in 
a half per cent, solution. As a mordant, phosphate of 
soda in one per cent, solution, to which tartaric acid is 
added in the proportion of f- oz. to \ oz. for 22 gallons. 
The following mordant is recommended for all blue 
and green aniline colours : water 22 gallons, phosphate 
of soda 2ith lbs., dextrine 2,1th. lbs., tartaric acid f oz. 
to 1 oz. 9. Imperial blue (cornflower blue) is ob- 
tained with water -blue D.N. in a one per cent, 
solution, the process being as in No. 6. Greg in dif- 
ferent shades is obtained by mordanting as 1 to 7, and 
maddering with elderberry juice or dogwood-berry juice 
(two brushes), then as a coating nigrosine or indu- 
line applied in a one per cent, solution. 10. Green. 
A light shade is given with new Victoria green, and a 
darker shade with extra brilliant green. 11. Violet : A 
one per cent, solution of methyl violet in water. When 
the skins have been dried they are plunged in water 
for a few seconds and are then allowed to drain like 
plates in a rack. A glazing machine may then be used 
for finish. 

Aniline Colours in Glove Dyeing. — While in the so- 
called kid leather used for boots aniline colours are the 
principal dye substances used, it is different with glac6 
leather, in which they are only adjuncts. The use of 
aniline colours in dyeing glove-leather is divided into the 



3 o4 LEATHER MANUFACTURE. 

following : — a. Dyeing with pure aniline colours, b. 
Maddering with pure dye-wood or berry-dye solutions, 
with a coating of aniline, and with the use of various 
metallic salts for darkening or turning shades, c. The 
mixing of different wood-dyes as maddering substances, 
with a coating of aniline, without employing any turning 
substances, d. A pure or mixed decoction of dye-wood 
or berries, shaded with aniline dyes. 

Dyeing with Pure Aniline Colours. — The process is 
almost entirely confined to so-called plunging colours, 
used to produce the most delicate shades for evening 
wear, the processes b, c, and d being carried out on a 
fiat surface. Phosphate of soda, with the addition of 
a very small quantity of tartaric acid, may be advan- 
tageously used. The dyeing substance is added to the 
bath in very small quantities, by which greater purity 
and regularity of colour are obtained. When the de- 
sired tone has been arrived at, a little dextrine is put 
into the bath and a little borax added. The skins are 
then well worked for five minutes longer, when they 
are taken out and allowed to drip, and are afterwards 
pressed. They are then treated with yolk of egg and 
salt, which must be greater in quantity than for kid 
leather. The aniline colours used are naphthol yellow, 
methanil yellow, eosine, phloxine, methyl violet, nigro- 
sine W., and induline N.N. 

The following table shows how the most usual shades 
required for opera and evening wear are respectively ob- 
tained by the old and new methods : — 

Old Method. New Method. 

Cream or Ivory. .Decoction of Persian berries, Naphthol yellow in a very 

with a trace of Brazil wood dilute form. 

Straw Persian berries Naphthol yellow. 

Pink Brazil wood with a little Two parts eosine with one 

cochineal part phloxine. 

Violet Alcoholic extract of logwood Methyl violet. 

Greenish Grey . . Elderberry juice, with a little NigrosineW., with a trace 

carmine indigo of lumiere green. 

Pearl Grey .... Elderberry juice and alco- Two parts nigrosine W. 

holic extract of logwood and one part induline 
N.N. 



DYEING LEATHER. 305 

Old Method. New Method. 

Yellowish Buff . .Persian berries and logwood Four parts naphthol yel- 
low and one part eosine. 
Reddish Buff. . . . Persian berries, Brazil wood, Two parts of metbanil 
(Flesh colour) and cocbineal yellow and one part 

pbloxine. 

In mixing the above solutions, precision in quantities 
must be observed, and it is recommended to make solutions 
of the strength of one-tenth per cent., in which there is one 
gramme (15'43 grains) of dye-stuff to each litre ("22 gallon) 
of water. It is best to make the solution in a cold state and 
in bottles of moderate size, so that they can be shaken to 
prevenl^the particles of dye-stuff from caking. After 
pressing, the skins are placed in a darkened and heated 
room well ventilated. The salts used for toning down 
colours are : copperas (sulphate of iron), sulphate of copper, 
(bluestone), sulphate of zinc, mixtures of copperas and 
bluestone, and potash alum, used in 1 per cent, solutions. 
The reader is referred to articles which appear from time 
to time in The Leather Trades Review for more elaborate 
details of aniline dyeing on leather. 



CHAPTER XXVI. 

MANUFACTURE OF WHITE LEATHER. 

Tawing as distinguished from Tanning. — Tawing Operations. — Kid 
Leather : Treatment of Kid Skins. — French Kid Leather. — Imita- 
tion Kid. — Continental Method of preparing Glove Leather. — Calf 
Kid for Uppers. — "White Sheep Leather. — Splitting Sheep Skins. 

Tawing, as distinguished from Tanning. — In the pro- 
cess of tanning, as we have seen, the gelatine of the skin 
undergoes a chemical change when brought into contact 
with tannin, by which tanno-gelatine is formed — a sub- 
stance not only insoluble in water, but which cannot be 
again separated into its two chief constituents, tannic acid 
and gelatine, by any known means. In the process of 
tawing, however, the skins are subjected to the action of 
alum and salt, which, although they convert the skins into 
a substance resembling leather in some of its attributes, 
cannot be said to form a true chemical compound with the 
gelatine, inasmuch as the three substances — gelatine, alum, 
and salt — can be again separated by treatment with water, 
as proved by the researches of Davy. 

The arts of tanning and tawing are therefore perfectly 
distinct, and have no relation whatever to each other. 
Some manufacturers of light leathers, however, carry on 
the process of tanning calf and seal skins, as well as the 
tawing of goat, kid, sheep, and other small skins. 

Tawing Operations. — The chief operations of tawing 
are : — 1. Soaking, or steeping in water. 2. Breaking, or 
scraping on the flesh side. 3. Liming. 4. Unhairing and 
fleshing. 5. Steering in a Iran-water drench. 6. Working 
on the beam. 7. Treatment with alum and salt. 8. Egging. 



WHITE LEATHER. 3 o 7 

The skins which are subjected to the operations of tawing, 
or alum-dressing, are those of the kid, the calf, the lamb, 
and the sheep, the first being employed to produce the 
well-known kid leather, from which the finest sorts of 
gloves and uppers of ladies' shoes and boots are made. 
Lamb skins, when prepared by the processes we are about 
to describe, form an imitation kid leather, from which the 
cheaper kinds of " kid " gloves are made. 

Kid Leather : Treatment of Kid Skins. — These skins, 
which are chiefly imported from Italy, are of very small 
size, and have the hair on. For leather to be employed 
for the finest quality of gloves, the skins are obtained from 
the young goats before they leave the mother to feed on 
herbage. The imported skins, being in the dry state, are 
first subjected to the operation of — 

Soaking, or steeping in water, in large tubs or vats, 
wherein they are allowed to remain for about three days ; 
at the end of this time the skins have become consideiablv 
softened, when they are next broken, as it is termed, on the 
flesh side. 

Breaking. — The skin is laid upon the beam, flesh side 
upward, and is then forcibly scraped with the blunt two- 
handled tool (Fig. 5), by which it is put into a better 
condition for liming. The effect of the scraping or rub- 
bing is to break down the fleshy matter attached to the 
skin, which had become hardened during the process of 
drying, and thus render the skin more readily acted upon 
by milk of lime. 

Liming. — After the skins have been broken they are 
immersed for two or three days in "old" lime liquor, 
being "drawn" occasionally, that is, removed from the 
pits by means of the small tongs (Fig. 48) and placed in a 
heap, being allowed there to remain for some time, after 
which they are steeped in "middling" lime liquor for 
Several days, and are finally immersed in strong lime 
liquor, in which they remain, being frequently drawn as 
before, until the hair can be readily removed from the pelt 
by the finger. In from ten to fourteen days, according to 
the temperature of the atmosphere, the skins are ready 



308 LEATHER MANUFACTURE. 

for unhairing. When the liming process is complete, the 
workman passes his thumb along the upper surface of the 
skin, when the cuticle, with its hair, peels off with perfect 
ease, exposing the bare pelt or corium. 

Unhairing. — The skins, after being removed from the 
lime-pits or tanks, are allowed to drain for a short time, 
when they are removed to the beam-room, where they are 
submitted to the process of unhairing, after which they 
are again soaked in lime water for several days. They are 
next fleshed, by which the pelt is brought to a tolerably 
clean condition. The lengthened steeping in the lime 
liquor, however, has the effect of forcing the lime into the 
pores of the skin to such an extent that, unless this were 
removed, the materials subsequently employed would not 
enter into the interior structure of the skin. To remove 
this lime and to open the pores, the kid skins are immersed 
in the bran drench. 

The Bran Drench is a mixture of bran and water, con- 
sisting of about 40 lbs. of bran to 20 gallons of water, 
which is allowed to undergo what is called acetous fermenta- 
tion, during which acetic acid is formed. By the action of 
the vegetable acid the lime within the pores of the pelt is 
converted into soluble acetate of lime, which is removed by 
subsequent washings. The skins are steeped in the bran 
liquor for some days, being frequently turned over, so as 
to equalise the action of the sour liquor. The branning 
operation is watched with great care, especially when 
treating such delicate skins as those of the kid. The 
branning has the effect of opening the pores of the skin 
besides "killing" the lime, as it is termed. 

Striking. — When the skins are sufficiently branned they 
are next struck, or scudded, by being worked on the beam 
with the blunt knife, by which albuminous matters, and 
any lime that may still remain within the pores, is effec- 
tually worked out. The skins are then again steeped in 
the bran drench for a day or two, after which they are in 
a condition to undergo the process of aluming. 

Treatment with Alum and Salt. — In this operation the 
skins are put into a kind of wooden drum or tumbler 



WHITE ^EATHER. 



309 




(Fig. 51). This machine, which is furnished with a door, 
either in its circumference or at one of its ends, through 
which the skins and alum 
mixture are thrown, is 
constructed so as to rotate 
upon an iron axle with 
the usual gearing. In the 
interior of the tumbler 
are fixed, at equal dis- 
tances, a series of per- 
forated breakers, upon 
which ihe skins, when 
the machine is in motion, 
fall, and thus become 
more intimately brought 
in contact with the alum 
mixture. These drums 
are also used for washing 
the skins. On each end 
of the drum are four small holes to admit cold air from 
without, and to allow the air warmed by the rotary motion 
of the drum to escape. The materials placed in the drum 
to act upon the skins for the inferior kinds of leather are 
alum and salt, in the proportion of about 12 lbs. of alum 
and 2 \ lbs. of salt to about 12 gallons of water for each 
200 skins. Sometimes, instead of employing the tumbler, 
the alum mixture is placed in a tub, and the skins steeped 
in the solution. Whichever method is adopted, the skins 
are only subjected to the action of the mixture for about 
five minutes, by which time the desired effect is produced. 
Egging — The Emulsion or Paste. — For skins destined 
to form the finest quality of glove leather, a peculiar kind 
of emulsion is employed, in which the yolks of eggs form 
a necessary ingredient. This emulsion is prepared by 
working up the yolks of eggs, in the proportion of one 
yolk per skin, with a little flour and water, the whole being 
vigorously worked up into a thin paste. Into this mixture 
the skins are put, one by one, and they are trampled upon 
by the naked feet until the emulsion has become thoroughly 



3io 



LEATHER MANUFACTURE. 




are 
and soft- 

(Fig. 52) 



absorbed. The effect of the aluming and steeping in the 
emulsion is to whiten and soften them, preventing the 
latter from hardening under the 
process of drying. 

Drying. — The tawed shins are 
next hung upon poles in the dry- 
ing-room, after which the} 1 
stretched out, smoothed 
ened upon the stake. 

Staking. — The stake 
is a wooden support, at the upper 
end of which is a blunt steel, semi- 
circular blade, somewhat like a 
cheese-knife. The skin, in a nearly 
dry state, is laid over this, and the 
workman takes hold of it with both 
hands and forcibly draws it over 
the knife in all directions, but more 
especially from side to side, by 
which it becomes stretched to its 
fullest extent, while at the same time all stiffness and 
rigidity are removed, and it becomes exceedingly soft and 
pliant. 

French Kid Leather.— The following method of pre- 
paring this famous leather is thus given by Wagner :* " The 
so-called Erlanger, or French tawing process, is employed 
only for the production of the glace, or kid leather, used 
for making gloves and ball-room shoes. The hair side of 
the skins intended to be converted into this leather is left 
unchanged, while as regards wash-leather gloves, which 
are treated (tanned) with fish oil, the hair side is cut off. 
The skins intended to be converted into kid leathers are 
treated with extraordinary care, and thus acquire in a very 
high degree all the good quality of alum-tanned (or rather 
tawed) leathers. As these skins are often intended to re- 
main white, or are dyed with delicate colours, the greatest 
care is taken to prevent any injury — as, for instance, con- 

* " A Handbook of Chemical Technology." 
1'h.D. Edited by William Crookcs, F.ll.S. 



By Eudolf Wagner, 



WHITE LEATHER. 3" 

tact with oak wood or with iron while wet. Two kinds 
of skins are employed for conversion into the better varie- 
ties of kid leather ; one of these, the more expensive, 
being the skins of young goats fed solely upon milk, the 
other being lamb skins. Each of these skins yields on an 
average two pairs of gloves. The leather of which ladies' 
ball-room shoes are made is obtained from the skins of young 
calves (so called calf kid). The preliminary operations of 
preparing this leather are exactly similar to those adopted 
for ordinary white leather, but the tawing operations are 
quite different, the skins being put into a peculiar mixture 
by whicji they are not only tawed, but simultaneously im- 
pregnated with a sufficient quantity of oil to render them 
soft and give suppleness. The mixture consists of a paste 
composed of wheaten flour, yolks of eggs, alum, common 
salt, and water. The flour, by the gluten it contains, aids 
the absorption of the alumina compound, and thus assists 
the real tawing. The starch does not enter into the com- 
position of the skins, while the yolk of eggs acts by the oil 
it naturally contains in the state of emulsion, this oil 
giving the kid leather that suppleness and softness which 
is so much esteemed in gloves. 

" It appears that emulsions made with almond oil (the 
so-called sweet oil of almonds, a fixed oil), olive oil, fish 
oil, and even paraffin, may be advantageously substituted 
for the yolk of eggs. The skins are thoroughly soaked 
and kneaded in this mixture, to which, in France, there is 
sometimes added two to three per cent, of carbolic acid, for 
the purpose of preventing the too strong heating of the skins 
when impregnated with the mixture and packed in heaps. 
The skins are next stretched out by hand and dried as 
rapidly as possible, by exposure to air. Having been 
damped, a dozen of the skins are placed between linen 
cloths and trodden upon to render them soft. After this 
they are, one by one, planed, dried, and again planed. 
Either by rubbing with a heavy polished glass disc, or by 
the appreteur, simultaneously with the application of some 
white of egg, a solution of gum, or of fine soap, a gloss is 
given to the skins, the hair side of which is the right or 



312 LEATHER MANUFACTURE. 

dyed side. The dyes are applied either by immersion or 
by brushing over the leather, the latter or English method 
of dyeing skins being more generally practised." 

Knapp states that very good white leather may be pro- 
duced by tawing the epidermis from lamb or goat skins in 
a saturated solution of stearic acid (stearin e) in alcohol, the 
leather thus produced being very soft, and whiter than 
ordinary glace leather, besides having a beautiful gloss. 

Imitation Kid. — For preparing this kind of leather 
lamb skins are emploj^ed. These skins are imported from 
the shores of the Mediterranean,* " in the wool," as it is 
termed, and this, being a valuable commodity, is removed 
with very great care before the operations on the pelt 
commence. Since the wool would be impaired if the skins 
were subjected to the process of liming, the skins are sub- 
mitted to a process of sweating, or putrefactive fermenta- 
tion, by which the wool becomes loosened from the pelt. 

Sweating. — The skins are first steeped, or drenched, in 
water for several days, after which they are broken on the 
flesh side. They are then again steeped, drained, and while 
still wet are transferred to a close room, sometimes an 
underground vault, the temperature of which remains nearly 
uniform all the year round. In this the skins are sus- 
pended from rails or bars. After a certam time ferment- 
ation commences, ammonia being given off in considerable 
quantity, together with a powerful and offensive odour. 
In about five days the wool becomes loosened from the 
pelt, but the skins are carefully examined from time to time 
before the process is complete, as it is of the greatest im- 
portance that the sweating process should be arrested and 
the skins withdrawn at the proper period, otherwise the 
pelt itself would suffer injury from the decomposition 
which ensues. 

When the sweating is completed, the skins are removed 
and worked on the beam, or slimed, as it is termed, that is 
scraped on the flesh side with the beam knife, to remove a 
slimy matter which exudes from the pores. The wool is 

* These skins generally measure about 20 inches by 12, and each skin 
produces leather for two pairs of small gloves. 



WHITE LEATHER. 313 

then removed, and this is afterwards cleaned and prepared 
for sale. The unwooled pelts are next steeped in the lime- 
pit for about a week to " kill " the grease, and after this 
they are fleshed on the beam. This having been done, 
they are next placed in a drench of sour bran liquor for 
several days to remove the lime and open the pores ; they 
are next treated with the alum mixture, and in all other 
respects treated in the same way as kid skins. 

Continental Method of preparing Glove Leather. — 
The substances used are alum and common salt as in the 
ordinary white tanning, but it is especially necessary to 
obtain alum free from iron, on which account this is selected 
in the most careful manner. Wheat flour and the yolks 
of eggs are then added in the following proportions. For 
a thousand skins of young goats or lambs, 25 lbs. of alum 
free from iron and 11 lbs. of common salt are dissolved 
in 150 lbs. of water. Next, a firm stiff dough is prepared 
from the yolks of 500 fresh eggs and 50 lbs. of the very 
finest wheat flour, to which only enough of the alum solu- 
tion is added to enable the dough to be mixed. When the 
egg-yolks and the flour have become very thoroughly 
and intimately blended, the remainder of the solution is 
gradually added, forming a thin pap of about the consist- 
ence of honey. This pap is called nahrung (nourishment, 
or food). Instead of the egg-yolks it is very common in 
southern France to employ pure olive oil, but even there, 
where hens are scarce and eggs dear, the eggs are employed 
by way of assistance when the finest kind of leather is to 
be prepared. The nahrung, or tawing paste, is placed 
in a vat, in which the skins are laid, being turned over 
several times, soaked through, and then a couple of per- 
sons with well- cleaned bare feet go into the vat and tramp 
about for an hour until the liquid part of the paste has 
been entirely taken up. After this has been effected other 
workmen relieve the tired trampers, and repeat the opera- 
tion with the skins which have already absorbed sufficient 
of the liquor. Next follows the stretching of the leather. 
Two workmen grasp a skin with both hands and pull it in 
every direction as powerfully as possible without tearing 



3H LEATHER MANUFACTURE. 

it. The skins are then dried quickly and given their 
lustre by covering the grain side with the ichites of eggs 
and rubbing them with a small disc of glass. 

The wheat flour used in making the paste has no effect 
upon the skin, and is only employed as a medium for dis- 
tributing the egg, oil, and alum evenly and more finely, 
and to present the alum as well as the oil (which are both 
necessary for the tawing) in the form of an emulsion, 
not too thin, otherwise the action upon the skin would be 
too rapid, and therefore irregular. The claim that the 
flour serves, by means of its starch constituent, to give the 
leather a white colour, could only be made by one who was 
entirely unacquainted with the matter. The starch flour 
does not dye white ; it covers the outer surface with white 
flakes, which fall off as soon as it dries. 

This fine leather has yet to be coloured ; for this pur- 
pose it is sorted into five or six different grades. Those 
skins which are entirely free from faults are allowed to 
remain white, being used for white gloves. Since these 
are the most delicate, they must also be the most free from 
faults. The second sort are employed for very clear 
colours, as yellow, chamois, flesh colour, or rose-red. The 
third sort is coloured dark yellow, lilac, or sea-green ; and 
the fourth or stronger colours, brown, violet, ash-grey, and 
green. The fifth grade is employed for all dark shades, 
and the sixth for black. The colour is applied either by 
immersing the wdiole skin, as is done with the lighter 
colours, or bjr rubbing the dye upon the grain side, which 
is the practice with the lighter tints, in order that the 
colour may not come off upon the hand when it becomes 
warm. The clear colours do not " crock " so easily, and 
the little that does come off is hardly noticeable. — Gerber 
Courier. 

Calf Kid for Uppers. — The preliminary operations in the 
preparation of this famous leather are : 1, Soaking and 
cleansing; 2, Liming; 3, Unhairing and fleshing; 4, 
Puring ; 5, Scudding ; 6, Drenching. The skins are 
next subjected to a series of operations termed dressing, 
the most important being : 1, Alum dressing ; 2, Drying; 



WHITE LEATHER. 315 

3, Seasoning ; 4, Staking ; 5, Shaving ; 6, Egging ; 7, 
Dj^eing and finishing. 

Soaking and Liming. — As the skins are received from 
the slaughter-house, they are thrown into a large tub of 
water to cleanse them from filthy matters, after which they 
are placed in the old lime-pits, in which they are handled 
as usual, after which they are treated in a stronger or 
" middle " lime, in which they are again handled ; and 
are afterwards immersed in strong lime, where they are 
allowed to remain (being drawn each day and returned to 
the same pit) until the hair is sufficiently loosened, when 
the skins are drawn and allowed to drain, after which 
they are removed to the beam-house to be unhaired and 
fleshed. 

*Unhairing and Fleshing by Machinery. — "We had re- 
cently the pleasure, through the courtesy of Mr. John S. 
Carlaw, of Blue Anchor Lane, Bermondsej^ of witnessing 
the unhairing and fleshing of calf skins by a machine of 
remarkable effectiveness. The blades of this machine, 
which is called the "Duplex Unhairing and Fleshing Ma- 
chine " (Janson's patent), are the invention of M. V. Gal- 
lien, and so constructed as to act upon the two surfaces of a 
skin, removing hair and flesh simultaneously, without in the 
least degree injuring the pelt. The inventor says : " The 
object of this invention is to give such an edge to the 
knives or blades of revolving cylinders in machinery, for 
shaving or otherwise treating hides and skins, that there 
may be little danger of making too deep a cut into the 
hide or skin, that the work may be done more efficiently 
than hitherto, and that the edge may be renewed with 
great facility. For this purpose an edge is given to these 
cylinder blades similar to that used on the ordinary cur- 
rier's or beamsman's shaving knife, that is to say, the edge 
is slightly bevelled, and in the bevelling a very thin feather 
or ' burred ' cutting edge is formed by the thread or turn- 
over of the metal. This thread or cutting edge may be 
constantly renewed by simply reversing the movement of 
the cylinder, and bringing the blades into contact with an 
emery plate, file or other sharpener, throwing up the 

* See Chap. xxxi. on Machinery Employed in Leather Manufacture for 
more recent information. — Ed. Fifth Edition. 



316 LEATHER MANUFACTURE. 

feather or thread, which is then adjusted by the ordinary 
tool or ' steel.' " 

The Duplex TTnhairing Machine has been practically 
adopted by Mr. Carlaw for a considerable time, and has 
proved to be a most satisfactory piece of mechanism. Mr. 
Carlaw, who frequently operates the machine himself, 
informs us that he can readily unhair and flesh in one 
operation, two and a half dozen calf skins per hour, or one 
in every two minutes, and the ease with which this is 
accomplished is really surprising. On examining some pelts 
after they had passed through the machine we were much 
pleased with the perfect uniformity and regularity with 
which the machine had done its work. A very useful 
feature in this remarkable apparatus is that the pelts are 
washed at the same time they are being unhaired and 
fleshed, by a series of jets of water issuing from per- 
forated horizontal tubes, which play upon both sides of 
the skin. After passing through the machine the skins 
are thrown into a tub of water until required for the next 
operation. 

Turing. — The 'pure — which is a lixivium of pigeons' 
dung in water — is kept in large tubs, and in this the un- 
haired skins are placed and allowed to remain, with fre- 
quent turning over, until they acquire a certain texture, 
by which the workman judges the operation to be com- 
plete, when they are removed and submitted to the 
operation of scudding. 

Scudding. — The object of this operation is to remove a 
film which remains upon the pelt after the hair has been 
removed, and also to force out from the skin the salts of 
lime formed by the action of the pure upon the lime 
absorbed by the skins in the lime-pits. The " scud " is 
removed by working the pelt upon the beam with the blunt 
knife, and after scudding the pelts are thrown into a large 
tub containing the bran drench. 

Drenching. — The skins are allowed to remain in the 
bran drench — which is kept in an active state of acetous 
fermentation — until the workman judges that the desired 
eifect is produced, which is determined by the appearance 



WHITE LEATHER. 317 

and feel of the pelt under pressure of the fingers. When 
the skins are first thrown into the drench, they sink to 
the bottom of the vessel, but as fermentation progresses 
(which is evidenced by a brisk evolution of carbonic acid 
gas) the skins rise to the surface, and the liquid becomes 
covered with a white froth or foam. After drenching the 
pelts are handed over to the dresser, in whose hands they 
undergo the subsequent operations which convert them 
into tawed leather. 

Alum Dressing. — A solution of alum and salt, consisting 
of three parts of alum to four parts of salt, dissolved in 
waters-is prepared and placed in large tubs, and in these 
the skins are placed and subjected to its action for about 
two weeks, or until the skins are properly " leathered," 
which is ascertained by pressing folds of the skin between 
the fingers, when, if the sharp bend of the skin assumes an 
opaque white streak, and not transparent, the skin is 
known to be properly tawed — not tanned, as some will 
persistently call it. 

Drying. — The alumed skins are next hung up in the 
drying-room, or stove, as it is sometimes termed, until 
quite dry, when they are called " crust goods," from their 
exceeding hardness. 

Seasoning. — The dried skins are next soaked in water 
for a short time, to season them for the process of staking, 
which is thus performed : — 

Staking.— The skin is laid across the perch, and the 
workman takes the stake, or " crutch " stake as some call 
it, in his hand, and placing the cross-handle under his 
right arm, holds the upright stock firmly in his hand, 
while with the left hand he seizes a corner of the skin, 
and forces the blade of the tool (which somewhat resembles 
the blade of a blunt cheese knife) from above downward, 
by which means he not only stretches the skin, but also 
renders it exceedingly soft and pliant. 

Shaving. — The skins are next shaved, either by hand or 
by the shaving machine (Fig. 67), by which the flesh side 
becomes uniformly levelled by reducing the substance of 
the stouter parts. 



3 i8 LEATHER MANUFACTURE. 

Egging. — The shaved sldns are now ready for the egg- 
paste or emulsion, which, with the skins, is put into a re- 
volving tumbler, and the machine kept in motion until 
the skins have thoroughly absorbed the composition, when 
they are withdrawn, stretched out, and conveyed to the 
dyeing-room. 

Dyeing. — The skins are first " mordanted " by being 
put into a tank containing urine, after which they are 
drained and folded lengthwise, flesh side inward. They 
are next placed in a tray containing a hot solution of log- 
wood. From this they are transferred to a second tray, 
containing a solution of sulphate of iron (copperas), which, 
with the former treatment, stains the grain of a deep blue- 
black. The dyed skins are now laid over a horse or 
tressel to drain, after which they are hung in the drying- 
room, where they are allowed to dry gradually. "When 
dry they are again seasoned with water, to prepare them 
for grounding, which operation is performed by scraping 
the flesh side with the " moon-knife," a tool somewhat 
resembling the round knife, but, being furnished with a 
horizontal handle at the lower part of the aperture, this 
tool is held in one hand, whereas the round knife is held 
bv both hands. The workman holds a corner of the skin 
depending from the perch with his left hand while 
scraping the skin with the moon-knife. After grounding 
the skins are laid flat on a bench or table, grain or coloured 
side up, and are then ironed with hot irons, much in the 
same way as linen. The skins are then sorted into sizes 
for market. 

White Sheep Leather. — The unwooled skins, as they 
are received from the fellmonger, are first steeped in the 
lime-pits to swell, soften, and cleanse them, being repeatedly 
drawn and allowed to drain upon inclined tables, which 
operations are continued for about three weeks. The skins 
are next rubbed on the grain side with a whetstone fixed 
into a wooden case with two handles, in order to free them 
from any adhering filaments of wool. They are then 
ready for the bran steep, which is made by mixing 40 lbs. 
of wheat bran in 20 gallons of water ; in a short time 



WHITE LEATHER. 3 r9 

fermentation supervenes, when acetic and other acids are 
liberated, which convert the lime within the pores of the 
skin into soluble salts, which subsequent working on the 
beam, alternated by washings, removes. It is usual to 
add some old bran liquor to the bran steep, to promote 
acetous fermentation. During the time that the slcins are 
in the steep they require to be frequently turned over, 
with careful watching, otherwise the pelts will suffer 
considerably from the action of the vegetable acids present 
in the fermenting liquor. In about two days in summer, 
and eight days in winter, the skins are said to be raised. 
At the-end of from two to three weeks they are ready for 
the next operation, termed aluming or alum dressing. 

Aluming'. — The alum bath for a hundred skins is com- 
posed of from 14 to 18 lbs. of alum and from 2^ to 3 lbs. 
of common salt, which are placed in a copper with 
12 gallons of water. When the mixture begins to boil, 
three gallons of it are passed through a colander into a tub, 
and into this twenty- six skins are introduced and worked 
one after another. After draining they are put together in 
the bath, and left therein for about ten minutes to further 
absorb the liquor. They are now ready for the next 
operation, which consists in treating them with a paste 
composed of flour and yolk of egg. 

The Paste. — This is formed by mixing (for a hundred 
skins) about 14 lbs. of wheat flour with the yolks of fifty 
eggs in the following way : the alum bath through which 
the skins have been passed is first warmed, when the flour 
is sprinkled into it and well stirred in ; the paste is well 
kneaded by additions of the solution, and it is then passed 
through a colander, by which it becomes smooth and clear. 
The yolks of eggs are next added, and the whole thoroughly 
well mixed by careful and vigorous stirring. The skins 
are first worked one after another in this paste, and then 
the whole number are placed together in the mixture, in 
which they are allowed to remain for a day. They are 
afterwards removed one by one, stretched upon poles, and 
left in the drying loft for a week or ten days, according to 
the season and the thickness of the skins. 



320 LEATHER MANUFACTURE. 

The effects of the paste are that the skins become 
whitened, softened, and protected from the hardening 
influence of the atmosphere, to which the oily matter of 
the eggs largely contributes. But for this treatment the 
skins would be unable to bear the severe processes of 
stretching or staking to which they are afterwards sub- 
jected to render them soft and pliant. 

Staking. — Before being worked on the stake (Fig. 52) 
the skins are steeped for a short time in clean water ; the 
workman then takes a skin and works it to and fro, flesh 
side downwards, over the semi- circular knife or blade of 
the stake with considerable force, by which it becomes 
stretched in length in the proportion of five to three. By 
this operation the whiteness of the skin is greatly im- 
proved, while it acquires the utmost degree of suppleness 
which it is susceptible of attaining. The skins are after- 
wards stretched by hooks and strings and hung up to dry. 
When dry they are worked on the stretching-iron, or they 
are polished with pumice-stone. Sometimes a yellowish 
tint is given to the skins by a mixture of whiting and 
yellow ochre in a moist state rubbed over the grain. After 
pumicing, the skins are smoothed with a hot iron, in the 
same way that linen is ironed, b}^ which the grain assumes 
a brilliant and glossy surface. 

Large sheep skins are also extensively converted into 
white leather by the process of tawing with alum and 
salt, for aprons used by workmen employed in iron works, 
which are found to resist the action of heat better than 
tanned leather. Sometimes also these skins are partially 
tanned with bark, and afterwards treated with alum and 
salt, for making leggings, gaiters, coarse gloves, &c, used 
by farmers and agricultural labourers. This latter trade 
is now chiefly carried on in the provinces. 

Splitting Sheep Skins, — Amongst the many ingenious 
contrivances employed in the manufacture of the different 
kinds of leather, none probably is so remarkable as the 
machine which is capable of cutting or splitting an 
unhaired skin into two or even three sections, without 
forming holes in either section. Although there are 



WHITE LEATHER. 321 

several modifications of the splitting machine— originally 
adopted, we believe, by the eminent firm of Bevington 
and Sons — a description of their now famous machine will 
doubtless suffice to indicate the principle upon which, skins 
are subdivided by machinery. The following details of 
this important machine are taken from an interesting 
work entitled Days at the Factories : — 

" Two rollers (Fig. 53) ranged horizontally in a frame 
are made to rotate in opposite directions, the vacancy 
between them being only just sufficient to admit a soft 
wetted sheep skin or pelt. The rotation of the rollers causes . 
the skyi to be drawn slowly between these ; but it cannot 
do so without encountering the blade of a very sharp knife 
which has a reciprocating horizontal motion, in such a 
position as to cut the skin into two thicknesses as it 
passes the knife, one half passing over and the other 
under the blade, a most ingenious contrivance for yielding 
to any inequalities which may occur in the skin. One of 
the rollers is made in several pieces, so adjusted that in 
passing over any thickened portions of the skin the 
common aperture between the rollers is widened at that 
part. It is one of the peculiarities in the construction of 
the machine that one of the semi-thicknesses or sections 
of the skin must be equable and level in every part, while 
the irregularities which might have existed in the 
original skin will be thrown into the section. Either 
section, the ' grain ' side or the ' flesh ' side, may have 
this equable thickness given to it according to the mode 
in which the skin is adjusted on the rollers ; and the two 
portions may have various ratios given to their thickness 
according to the position of the vibrating knife opposite 
the opening between the rollers. A sheep skin of the 
usual size occupies about two minutes in splitting, during 
which time the knife makes from 2,000 to 3,000 vibratory 
motions to and fro, cutting a minute portion of the skin 
at each movement." 

A representation of skin-splitting is shown in the sketch 
(Fig. 53). These machines are now made to split skins 
into three equal sections or slices, the grain being used 

Y 



322 LEATHER MANUFACTURE. 

for skiver, the middle portion for parchment, and the flesh 




1'is. 53. 



side, being of unequal surface, and therefore unsuited for 
conversion into leather, being used for glue-making. The 




Fig. 54. 

American Union Splitting Machine, used to some extent 
for splitting tanned leather, is shown in Fig. 54.* 

* See also Chap. xxxi. p. 412. — Ed. Fifth Edition. 



CHAPTER XXVII. 

CHROME LEATHER MANUFACTURE. 

Preliminary Operations. — Liming and Unhairing. — Fleshing. — Puring 
or De-liming. — Scudding. — Chroming Operations. — Striking-out and 
Shaving. — Dyeing Chrome Leather. — Fat-Liquoring. — Dyeing 
Black. — Putting or Striking Out. — Oiling and Drying. — Staking or 
Softening. — Seasoning. — Glazing. 

In the development of what is known as the chrome 
process, the past few years have witnessed a complete 
revolution in leather-making, and one which has had 
far-reaching consequences upon the producing and con- 
suming side of leather manufacture in glace kid, box and 
willow calf, sides, belting and harness, &c. We have 
had an absolute departure from the older forms of tanned 
leathers, and it is only fair to describe the success of 
chrome leathers as the outcome of American perseverance 
and ingenuity in exploiting technical chemistry for the 
purposes of commercial industry. 

Only a few years ago the man who ventured to express 
his belief that " chemicals " would take the place of oak 
bark for leather-making was looked upon as a dreamer ; 
now the French tanner of bark upper leather is largely 
displaced, America has captured the cream of the world's 
glace leather trade, and British and Continental manu- 
facturers have taken up chrome leather-making with a 
fair amount of success. 

It may be permissible here to briefly summarise the 
history and technique of the process, for it is certain 
much of the business of the leather manufacturer of the 



324 LEATHER MANUFACTURE. 

future will depend upon the successful catering for this 
particular branch of the industry. 

As far back as 1858, the late Professor Knapp brought 
out a chrome process, but it created little notice in the 
industrial world, and was regarded as of only chemical 
interest. In 1879, Heinzerling patented a form of chrome 
leather ; this, again, attracted little attention, and it was 
left to the ingenuity of August Schultz, of New York, to 
bring out an idea commercially valuable. His patent 
was dated January 8, 1884 ; and although it has now 
expired, it has been the subject of endless litigation in 
America, which always ended in favour of the patentee. 



The Original Schultz Patent. 

Briefly put, the principle of the chrome tannage de- 
pends upon the formation of chromic oxide in the skin, 
this being brought about by the reduction of chromic 
acid with suitable agents. As a good deal of the lighter 
class of chrome leather is still made in much the same 
way as by Schultz's method, it will be advantageous to 
give here his original specification. 

"This invention relates to a new process for tawing 
hides or skins, said process consisting in subjecting said 
hides or skins to the action of compounds of metallic 
salts — such as bichromate of potash — and then treating 
the same with hyposulphite of soda, by which term is 
understood that salt which is more recently sometimes 
called ' thiosulphate of soda ' (Na 2 S 2 3 ). 

"In carrying out my process I unhair the raw hides 
and prepare them in the same manner in which they are 
made ' ready ' for tanning. If the hides have not been 
pickled, I subject them to the action of a solution of 
bichromate of potash in the presence of an acid — such as 
hydrochloric acid — or, if the hides have been pickled 
they may be treated in a solution of bichromate of potash 
in water without the addition of an acid. 

"In this solution the hides are left for a shorter or 



CHROME LEATHER MANUFACTURE. 325 

longer time, according to their thickness and to the 
strength of the solution employed. A skiver or the face 
of a sheep skin can be done in a strong solution, as above 
described, in about fifteen minutes, while a full skin 
' roan ' would require in the same solution about one 
hour. I call the solution 'weak' if it contains 5 per 
cent, or less of the weight of skins of bichromate of 
potash, and I call the solution ' strong ' if it contains 
more than 5 per cent, of bichromate of potash. It is 
not material, however, how strong the solution is. 

" The skins are completed if small pieces cut from 
the thickest parts of said skin show that the solution 
has entirely penetrated. The skins are then ready to 
be taken out, and after the adhering liquor has run off, 
the skins are introduced into the second solution, which 
consists of hyposulphite of soda dissolved in water, and 
adding an acid, such as hydrochloric acid. The solution 
may be strong or weak of hyposulphite, and the quantity 
of acid used at first may be less than requisite to split up 
the entire quantity of hyposulphite, and more acid may 
be added if the skins show that more is required, which 
is indicated by the colour of the skins. When they 
are done they show a whitish, bluish, or greenish colour, 
according to the time they are kept in the hyposulphite 
solution. 

"A skiver which first has been exposed to the action 
of the bichromate for fifteen minutes will be ready by 
remaining in the hyposulphite solution about twenty 
minutes. For thicker skins a proportionately longer 
time is required. For some skins — such as calf or steers' 
skins — it is desirable that the same, after having been 
withdrawn from the second or hyposulphite solution, shall 
be returned to the bichromate solution, which imparts to 
them a brownish colour, and leaves them in a favourable 
condition to be coloured black. The colouring can be 
clone after the skins leave the hyposulphite solution, and 
after they have been exposed for the second time to the 
bichromate solution. The leather coming from the 
hyposulphite solution is especially adapted for light or 



326 LEATHER MANUFACTURE. 

dark colours, and by proper dyeing methods better and 
brighter colours can be produced than on leather done by 
tannin. After the leather is treated in the manner above 
indicated, it may be coloured, soaped, and greased in the 
usual way. 

" Leather can also be made by reversing the operation 
and first soaking the hides in a solution of hyposulphite 
of soda and then exposing them to the action of the 
bichromate solution. By using the solutions indicated 
at a heat of about 80° Fahr., the process will be done in 
a shorter time than if the solutions are used cold. 

" By my process the gelatine contained in the hides is 
rendered insoluble by means not injurious to the leather. 
If leather made by tannin is put in a strong soda solution, 
the tannin is extracted, and a dark brown liquor is formed. 
If leather made by my process is put in a strong soda 
solution, the liquor obtained shows only a little milky 
colour. 

" Leather made by my process is very strong, soft, 
elastic, and my process is applicable to hides or skins 
of every description." 

It is obvious that many improvements in the manipula- 
tion of the above process have been introduced since 
it was brought out. As a matter of fact, however, the 
main principle of the impregnation of the skin with 
chromic acid remains much the same, and excellence is 
obtained by a variety of small points in the subsequent 
mechanical manipulations, mainly by the employment 
of ingenious machinery and suitable materials. Theo- 
retically, chrome leather is easy to make, but in practice 
it is very difficult to attain any great amount of com- 
mercial success without a large expenditure, enterprise, 
and technical knowledge. 

Chrome leather may be made by two methods, which 
are technically known as the " one-bath " and the " two- 
bath " methods. Opinions differ as to the results obtained 
by each, but, generally speaking, the heavier leathers, 
such as harness, belting, picker, and calf leathers, are 
obtained by the use of the one-bath method, which is 



CHROME LEATHER MANUFACTURE. 327 

very simple in its application, and depends upon the use 
of a dilute solution of a basic chromic salt, the goods 
being subjected to its action in gradually increasing 
strengths until struck through. This method will be 
dealt with later on. 

Light goods, however, such as glazed goat and sheep 
skins, are generally treated by the two-bath process, and 
the following summary may be taken as fairly repre- 
sentative of the method now in vogue : — 

Chrome or Glac£ Goat Skins. 



The immense demand for goat skins has led to a regular 
advance in the price of the raw material, and it has been 
humorously said that where a goat is wandering, there 
waits an American for him to die. It will, therefore, be 
gathered that the demand for skins is very great, so much 
so that there is now no corner of the world which has not 
been drawn upon for supplies. The enhanced value of the 
pelt, too, has led to increased attention being devoted to 
its primary preparation for storage and transit, and skins 
are now carefully treated with various compounds for more 
complete preservation. A large business has sprung up, 
for instance, with Australia and JSTew Zealand in the 
export of what are known as pickled skins. These are 
put through the preparing process of soaking, liming, and 
unhairing, fleshing, scudding, &c, when they are given a 
bath of weak sulphuric acid solution. In this they rapidly 
swell ; salt is then added, and the skins become reduced, 
and are in reality pickled with a sort of glauber salt. 
The result is fairly good, but the recent Society of Arts 
committee, appointed to deal with the deterioration of 
bookbinding leather, has pointed out that the action of 
the acid often tends to a serious weakening of the animal 
fibre, and that the resultant leather is sometimes not to 
be depended upon. The result has been that other pre- 
servative agents have been employed, such as formic 
and acetic acids, and it is claimed their use shows a 



328 LEATHER MANUFACTURE. 

distinct improvement upon the ordinary pickling or 
salting methods. 

Various proprietary articles have also been put on 
the market for the purpose, and one especially has given 
remarkably good results, viz. Atlas Preservative " S," sold 
by the Atlas Preservative Company, Windmill Lane 
Wharf, Deptford, London, S.E. This, it is claimed, per- 
fectly preserves skins and hides in a fresh condition, and 
no difference can be detected in the finished leather when 
compared with that made from fresh-slaughtered goods. 
This preservative may be used with a little salt in such a 
manner as to keep the skins in a damp and moist condi- 
tion, or painted in a weak solution on the flesh side, and 
the skins subsequently dried out and baled for transport. 
As it is usual to find about ten per cent, of badly damaged 
skins in certain grades of goat skins, the fact that a method 
has been evolved to stop this economic waste cannot be 
too widely known. Experts have reported very favour- 
ably on the Atlas Preservative, and good leather has 
been made from skins treated in all parts of the world. 

Preliminary Operations. — A good deal, of course, 
depends upon the sort and condition of the various 
goat skins, as regards the first stages of glace goat manu- 
iacture. Skins, as before mentioned, are of world-wide 
origin, and the pelts from Southern Europe, South 
America, China, and India all show various charac- 
teristics which necessitate differences in treatment. The 
most esteemed skins perhaps are what are known as 
Patna skins, coming from India. These, generally 
speaking, are of good quality and fibre, and produce a 
fine and close grain, which is a sine, qua non in kid 
manufacture. Taking this class, then, as representative, 
the procedure is as follows : The skins are first soaked 
in plenty of clean water; the time varies according to 
the condition of the skins, but about two or three days 
should be sufficient to bring them back to a good soft 
condition. This is greatly facilitated by the addition of 
a little borax or soda to the soak liquors, about one pound 
of borax per three hundred gallons being considered 



CHROME LEATHER MANUFACTURE. 329 

sufficient for the purpose. Sulphide of sodium is also 
used for the same purpose, and has a decided effect 
on softening the hard nature of the skins and getting 
them into condition for liming. Care should, of course, 
be taken that putrefaction does not set in, and this may 
be guarded against by changing the first water after 
about twenty-four hours, and after drawing the skins, 
to put them into the second soak treated with some 
disinfectant. 

If the skins are very hard and dirty, a "breaking 
over " between the changes of water is beneficial. This 
breaking over is done in small tanneries by well stretching 
and working the wet skin with a blunt tanner's knife over 
the half-round beam. In the large chrome works, how- 
ever, this mechanical softening is at times done by the use 
of the fulling stocks (see Fig. 6). The pounding motion of 
this machine is very effective where short-haired skins 
are under manipulation, and from twenty minutes to 
half an hour is usually ample time to break down the 
most obstinate pelt. Some classes of skins may be 
softened effectually in a drum tumbler ; but however 
softened, the general theory should be to bring the pelts 
back as far as possible to their original soft and pliant 
condition. 

Liming and TTnhairing. — In the manufacture of glace 
goat, lime and arsenic sulphide are the materials gener- 
ally favoured for depilation. Experience has shown that 
the action of lime loosens the hair, distends the fibres of 
the skin, assists to neutralize the natural fat, and so far acts 
upon other constituents not necessary to leather-making 
that they may be mechanically worked out later. In 
practice it is common to add about 5 lbs. of "red 
arsenic " to about 100 lbs. of lime slacked in a large tub. 
The lime should be thoroughly slaked with enough water 
to moisten it, and the arsenic added and mixed thoroughly 
with the lime, and the whole mass well stirred. A minor 
objection is that sulphuretted hydrogen is evolved during 
the process, so that it should be carried out in the open 
air, if possible. The arsenic helps to shorten the time of 



330 LEATHER MANUFACTURE. 

the depilating process, whilst it also greatly assists in 
producing leather of a supple texture and a smooth 
grain. 

When the above quantities of lime and arsenic are 
dissolved the solution is thrown into the pit with sufficient 
water, care being taken that no undissolved particles or 
stones find their way in. No definite rule can be laid 
down, but the quantities stated are sufficient to unhair 
from five hundred to six hundred skins. After the skins 
have laid in the solution for a day or so they are hauled 
up and laid up to drain, the solution being well plunged 
up before the skins are re-entered. It may be also 
necessary to strengthen it by the addition of a little more 
lime and arsenic after a day or two, but a good deal 
depends upon whether old or new liquors were used at 
the start ; generally speaking, it is inadvisable to use 
much lime toward the end of the process, as it has a 
tendency to produce a coarse grain on the finished leather. 
In some factories it is considered safe to start with a liquor 
showing about 3° Twaddle, and finishing up with one at 
about 5° or 6°. The time taken for depilation varies, but 
may be approximately put at from ten to fourteen days, a 
good deal depending upon the condition of the skins, the 
temperature of the solution, and the handling the goods 
receive. Some manufacturers profess to have had good 
results in the use of sulphide of sodium for unhairing. 
This has the disadvantage of practically destroying the 
hair, and as this in some classes of goat skins is valuable, 
the sulphide is not much favoured for that reason. Various 
methods are followed out where sulphide is used ; it may 
be painted on the flesh side of the skins, or the skins 
may be thrown into a weak solution ; or, again, it may be 
used in conjunction with lime as in the case of arsenic 
sulphide. However, as practically all the successful 
chrome goat manufacturers use the arsenic limes, it is 
not perhaps advisable to take up valuable space by deal- 
ing further with the sulphide of sodium methods. If 
sulphide of sodium is used in conjunction with lime, 
about a third of the former is sufficient ; the goods are 



CHROME LEATHER MANUFACTURE. 331 

worked much as in the case of lime, and the skins are 
ready for unhairing in about six to ten days, according to 
substance, &c. When the skins have had enough lime they 
are usually washed in water to cleanse them as far as possible, 
and if the shanks, &c, have not been removed before, they 
are trimmed away when the skins are ready for unhairing. 

The unhairing, being a very simple operation, is often 
done by hand on the half-round tanner's beam with a 
blunt knife; of late years, however, this operation has 
been done by machine. The only drawback to the use 
of the machine for unhairing is that the holey and de- 
fectiva skins are rather harshly treated, and if great care 
is not used a skin is often so torn by the action of the 
spiral knives that it is practically worthless. 

Fleshing. — In nearly all large chrome leather works 
goat skins are fleshed by machine. The operation is, 
however, comparatively simple, and in countries where 
there is an abundant supply of cheap labour, it is easy to 
train men to flesh goat skins in the old-fashioned way with 
the ordinary tanner's knife. Goat skins, as a rule, are not 
very fleshy, and most of the loose tissue can be removed 
by the " brushing " or scraping edge. The machine 
usually employed for fleshing is illustrated at Fig. 74, 
the skin being spread flesh outwards on a special rubber 
roller, and subjected to the action of a cylinder fitted 
with spiral knives. A modified form of the machine, 
shown as Fig. 64, is also often used for fleshing. The 
work done by the machine answers on the whole very 
well, and is cheaper in Europe and America than the 
hand process could be. Many small glazed kid manu- 
facturers use the same machines for unhairing, fleshing, 
and scudding, using different cylinders for the various 
purposes. As the output of chrome kid, however, has 
to be very large to ensure a profit, this is not to be 
recommended, except for exceptional cases, or for the 
experimental stage of glazed kid manufacture. In 
machine fleshing great attention should be paid to the 
cutting cylinder and to the rubber bolster, otherwise the 
work will be defective, and a good deal of damage ensue 



332 LEATHER MANUFACTURE. 

to the skins under operation. In no case should fleshing 
be entrusted to any but a most intelligent man, who 
should be encouraged by good wages to become a 
thorough master of the operation. 

Puring or De-liming. — To ensure the production of a 
good tough and elastic leather with a fine " break " and 
grain, it is necessary to pay special attention to this 
process. If lime be present in the skins when they go to 
the chrome bath, it is turned into sulphate of lime, and 
the leather is hard and often brittle. After fleshing, the 
skins are trimmed where necessary, and well washed in 
plenty of soft water to remove as much lime as possible, 
and, after draining, are ready for the puring operation. 
All sorts of de-liming agents have been tried, such as 
sulphuric and lactic acids, &c, but experience has shown 
that in the majority of cases the old and disagreeable 
excrement pure gives the best results. Some manu- 
facturers, however, claim to have used " Erodin," intro- 
duced by Mr. J. T. Wood, of Nottingham, and Drs. Popp 
and Becker, of Germany, with good results. This bate, 
or pure, depends for its effect upon the bacteriological 
action, and was invented after much patient experiment- 
ing had enabled the inventors to isolate the active 
organism, and to put a culture and a cheap medium for 
its propagation before the trade. 

Space, however, will not admit of enlarging upon the 
various de-liming agents which have been tried, and as 
dog-dung is by many still regarded as the best material 
for glace goat, we will devote our limited space to a con- 
sideration of its use. In puring it is necessary to 
remove the dissolved gelatinous substance, the hair 
sheaths, fat glands, &c, and the lime soap produced 
by the action of the lime on the natural fat of the skin. 

For the heavier kinds of hides and skins, hen and 
pigeon dung is used for bateing, but in England dog- 
dung is almost exclusively employed for the process in 
goat-leather manufacture. It is usually obtained from 
dog-kennels, and as it varies in strength and charac- 
teristics, it is difficult to give any definite directions for 



CHROME LEATHER MANUFACTURE. 333 

its use. As dog-dung rapidly ferments it should not be 
exposed much to the air. In many works it is mixed 
with a little water to a paste, and kept in this way, and 
in no case should the dung be used until it has been 
allowed to ferment for six or seven days. In practice a 
few pails of the semi-liquid dung is added to water at a 
temperature of about 90° Fahr., the dung being first 
strained through a coarse bag to remove bits of bone, 
gravel, and other sediment. The skins soon begin to 
" fall " in the solution, or lose their plumpness, and are 
considered to be sufficiently pured when the grain 
retains-the impression of the thumb or fingers. In large 
works this puring operation is performed in paddles, 
the strength of the concoction and the time the skins 
are allowed to remain in it varying according to the 
system followed out or the ideas of the pureman, who, 
by the way, should be an experienced and skilled 
workman. 

Scudding. — After the skins have been pured, drenched, 
or both, as the case may be, they are then carefully 
worked over on the grain side to remove the lime-soap, 
pigment, fat, short hairs, and other matter. This is also 
a very necessary operation, as if much " scud " is left in 
the skins, the leather on finishing refuses to glaze pro- 
perly, whilst any hairs remaining would quite spoil the 
look of the finished article. 

In some places the scudding is still done on the 
tanner's beam with the half-round slate " knife," the 
workman thoroughly extending and working out the soft 
and flaccid skin in every direction. It is usual now, 
however, to do this operation by a machine similar to 
that described in fleshing, the skin being subjected to 
the action of a cylinder into which slate tools are let 
in, the bolster being of stout rubber. The work is done 
fairly well and very cheaply ; but it is a good rule to 
have the skins examined and to rectify any faults by hand 
on the beam. Some of the short-haired goat skins, such 
as Patnas, often scud very badly, and want a good deal 
of attention to get a clean and fine grain. Others, again, 



334 LEATHER MANUFACTURE. 

such as Chinese skins, scud well and make good clean 
leather with comparatively little trouble. 

Too much attention can hardly be paid to this branch 
of glace leather manufacture, and attempts at economy 
here may turn out disastrously later on if the pelts are 
not freed from impurities and short hair. It is even 
necessary, in extreme cases, to lightly shave the grain 
where the liming or puring operations have not been 
carried out thoroughly. After scudding, the skins are 
either left for a few hours to drain, or, if necessary, are 
washed in plenty of clean water. Some manufacturers 
wash in the paddle in a dilute lactic acid solution, and 
then in a weak borax solution, 1 lb. of the latter to about 
150 to 200 gallons of water being sufficient. 

Chroming Operations. — No two glace goat makers 
follow quite the same procedure, and whilst some see an 
advantage in giving the skins a pickle of acid and salt 
before proceeding to the actual chrome tanning, others 
dispense with this process as unnecessary. If the former 
process is clone, however, one American authority says 
that 10 lbs. of salt for each 100 lbs. of drained pelt, dis- 
solved in 15 gallons of water, is sufficient. The skins are 
run in a drum with this solution for about fifteen 
minutes, and the acid given. This is prepared by mixing 
2 lbs. of muriatic acid (hydrochloric) in a pail of boiling 
water and cooled with two pails of cold water. This 
is added to the skins in the drum, which are run for 
another fifteen minutes, when the skins are ready for the 
chrome bath. 

The saturation of the lighter pelts, such as calf and 
goat, with the chromic acid is invariably carried out in 
the paddle or drum, and in all large works separate ones 
are used for tanning, reducing, washing, &c. Care should 
be taken to see that the driving arrangements are always 
in good order, as a breakdown often involves serious 
trouble and loss. 

The chrome bath is prepared by dissolving bichromate 
of potash in boiling water which is acidified with 
hydrochloric acid, and this is added to the goods 



CHROME LEATHER MANUFACTURE. 335 

whilst they are running in a suitable quantity of water. 
The quantity of bichromate of potash is calculated on 
the weight of the wet drained skins, and varies from 
4 to 6 lbs. per cent. In practice, about 15 gallons 
of water to 100 lbs. of skins is recommended. The 
amount of bichromate of potash is not very material, 
but from 5 to 6 lbs. per cent, of wet pelt is a safe margin. 
One method is to dissolve 6 lbs. of bichromate of potash 
in 20 gallons of water, to which is carefully added 3 lbs. 
of acid. Some authorities also advise the addition of a 
few pounds of salt to the solution, but of this the writer 
has had. no experience. In practice it is advisable to 
dissolve the bichromate of potash in a suitable quantity 
of hot water, and add the solution to the goods whilst in 
motion in the drum or paddle, the requisite amount of 
acid being added in successive stages. 

The skins are padded in the acidified liquor until they 
assume a yellow colour throughout, the process being 
finished when a cut in the thickest part of the skin shows 
complete penetration. When completely struck through, 
the skins are taken out of the acid solution, horsed up 
carefully, care being taken to avoid light and wrinkles, 
and the excess of liquor struck out by machine. The 
next process, technically called " reducing," is the re- 
duction of the chromic acid. In many works the skins 
are first dipped one by one into a weak solution composed 
of about 4 or 5 lbs. of hyposulphite of soda dissolved in 
15 gallons of water; this is sufficient for 100 lbs. of wet 
pelt. This dipping process is assumed to somewhat " set " 
the grain side of the leather, and so prevent the tendency 
of wrinkling or coarseness caused by the sharp action of 
the reducing bath. This latter is usually done in paddles, 
10 lbs. of hyposulphite of soda being dissolved in 20 
gallons of water and added to the proper amount of 
water in the paddle. Five per cent, of muriatic acid, 
calculated on the wet weight of the skins, is then added, 
and the skins paddled in this until they lose their original 
yellow colour and assume a bluish-green tint through- 
out. It is a good plan in practice to so arrange the 



236 LEATHER MANUFACTURE. 

work that the chroming begins in the morning and is 
completed in the evening. It is of the greatest im- 
portance that the reduction should be complete, as no 
amount of work in the subsequent stages will ever make 
a first-rate article. It is also an advantage if the skins 
are sorted into various substances before chroming, other- 
wise the penetration is uneven throughout the pack, and 
the heavy skins may be under-tanned. It might also be 
mentioned that the reduction should be done in a well- 
ventilated room, as the fumes given off during the 
process are both disagreeable and detrimental to the 
health of the workman. When the skins are perfectly 
chromed throughout they are taken out of the paddle, 
and are then given a prolonged washing in a weak borax 
solution, followed by plenty of water. This will neutra- 
lise any free acid remaining, and should be continued 
until no reaction is shown by the leather when tested with 
litmus paper. 

Striking-out and Shaving. — The skins are next well 
struck out by machine, and passed on to the shaving 
machine. In the case of goat skins it is often only 
necessary to level the necks and backs of the skins, 
although if of stout substance they will require reducing 
all over. This process must be done with judgment and 
by careful operators, if damage to the leather is to be 
avoided. The fact, too, that there is a certain element 
of danger in working the shaving machine should 
make the selection of operators worthy of more than 
ordinary consideration. The cost of machine shaving is 
not great, and varies from about a penny to threepence 
per dozen. 

Dyeing Chrome Leather. — If the skins are to be 
divided into black and coloured work, the sorting must 
be done at this stage ; only the finest and most perfect 
grain skins are suitable for colouring fancy shades, so 
that those which are marked, imperfect on the grain, or 
greasy, should be put for black work. At the same 
time it must be remembered that the quality of the 
black skins is obviously deteriorated by sorting the 



CHROME LEATHER MANUFACTURE. 337 

best skins out, so that a good deal of judgment is 
required. 

Dealing with the black skins, the first operation is to 
mordant them for dyeing. This is technically termed 
" blue-backing," as it has the effect of colouring the flesh 
side of the skins a sort of bluish purple. The usual method 
is to immerse the skin in a solution of warm logwood for 
about half an hour, using the paddle or tumbler for the 
purpose. Hemolin is also used for the same purpose, but 
it is said the skins lose a slight fullness imparted to them 
by the more astringent logwood. An American authority 
says the following method of dyeing black produces a 
very satisfactory result. The skins are drummed in a 
liquor made up of about 4 ozs. of liquid sumac extract in 
5 gallons of warm water, this being the quantity required 
for about a dozen skins. The skins are then dyed with a 
purple aniline, about 3 ozs. being sufficient for a dozen 
skins. The skins are then passed through logwood or 
hemolin liquor, and then through the iron striker, and 
finished off with a bath of aniline black at a temperature 
of about 130° Fahr. Nigrosine, methyl violet, and 
other anilines are also used for blue-backing, but in 
many cases glace leather manufacturers prefer to depend 
mainly upon the use of the logwood solution, assisted by 
hemolin, &c, which they consider give the best results 
generally. 

Fat-Liquoring. — When the skins are blue-backed 
they are then ready for the next operation, termed " fat- 
liquoring." This is necessary for the thorough lubrica- 
tion of the fibres, and to produce a supple and tough 
leather. 

Experience has shown that the most convenient time 
for the process is after the logwood mordanting bath, 
although the process is sometimes done after the final 
dyeing. Broadly speaking, the fat-liquor is simply an 
emulsion in water of some oily or fatty material, or 
materials. Most leather manufacturers have their own 
special mixture. Neatsfoot oil, egg yolk, olive and 
castor oils, special soaps, also sod oil and degras, are aU 

z 



338 LEATHER MANUFACTURE. 

used, but the first two named materials are perhaps the 
best for kid leather, which has to bear a high polish and 
a perfectly clear surface. Turkey red oil has also been 
recommended for the purpose. Professor H. R. Procter 
states that Turkey red oil (which is sulphated castor oil) 
makes a convenient fat-liquor mixed with, warm water 
without soap, and has been advocated where delicate 
colours are to be dyed after fat-liquoring, although, it 
is said to tend toward making the leather tender and 
hard. 

Fat-liquors should be as nearly neutral as possible, 
although if any acid has been left in the skins a neutral 
fat-liquor will cause a deposit of gummy matter on the 
grain almost impossible to get rid of. Procter gives 1^ 
per cent, of castor oil soap and f per cent, of castor 
or olive oil on the wet weight of the pelt as being 
serviceable. Another fat-liquor which is claimed by 
an American writer to give great softness to the skins 
is made as follows : 20 lbs. of soft soap and 40 lbs. of 
sod oil is thoroughly emulsified in 50 gallons of water. 
The soap should first be boiled in a few gallons of water, 
and the oil added, and enough water then added to make 
up the 50 gallons. About 2 gallons of this fat-liquor per 
dozen is sufficient, and the liquor should be used in the 
drum at a temperature of 130° to 160° Fahr. 

For fine glazed kid the writer has always obtained 
good results with suitable soap, neatsfoot oil, and egg 
yolk for the fat-liquor, which is safe and easy to prepare. 
Fifty gallons of this may be prepared by cutting up 
10 lbs. of good soap and boiling in 50 gallons of water, 
adding 3 or 4 gallons of best neatsfoot oil by instalments 
until thorough emulsification takes place. It is con- 
venient in practice to use only a part of the 50 gallons 
for emulsifying, and to add the remainder cold, or nearly 
so, to bring down the temperature to about 90° Fahr. 
before adding the egg yolk ; otherwise the latter will be- 
come more or less insoluble. Two or three gallons of this 
fat-liquor per dozen is sufficient, although it is obvious a 
good deal will depend upon the condition and size of the 



CHROME LEATHER MANUFACTURE. 339 

skins. If any trouble is found in emulsifying, a little 
borax added to the boiling liquor is usually beneficial. 

Skins should be allowed to drain before fat-liquoring, 
and the fat-liquor added to the goods quickly whilst the 
drum is in motion. About half an hour is sufficient for 
the leather to absorb the fatty matters, and a little 
experience in handling the skins will soon indicate the 
proper time and quantities required. 

At the completion of this process the skins are care- 
fully folded grain out straight down the back, and 
allowed to lay on a suitable horse for a day, or more, 
to enable the fibres of the leather to have the full benefit 
of impregnation with the greasy matters. 

Dyeing Black. — After the fat-liquoring operation the 
skins are then ready for dyeing black. This may be done 
either by brushing them with the " striker " on the table, 
or by passing the skins through the logwood and iron so- 
lution in suitable vats or trays. Some manufacturers have 
also tried dyeing chrome goat in the drum, but the writer 
prefers the tray method for several reasons, which would 
take up too much space here for discussion. The dyeing 
liquor varies somewhat in composition, but the following 
is a safe formula for a black striker : Dissolve, by boiling 
in 40 gallons of water, 5 lbs. of copperas and about 
24 ozs. of blue vitriol, adding 1 lb. of ground nut-galls. 
The skins are first folded down the centre grain out, and 
perhaps slicked down with a smooth glass to protect the 
flesh side as much as possible, and are then passed in 
small packs through a strong logwood liquor, which is 
all the better if boiled with a little fustic wood. After 
this they are worked through the striker in a dilute form 
until a deep black is obtained. As the iron striker is 
rather inclined to roughen the grain if used too strong, 
care must be taken to guard against this. It is more 
difficult to obtain a good chrome black than would be 
supposed, and the dyeing should be executed in a light 
part of the works, and entrusted to the care of one 
who has had some experience in the matter, otherwise 
"bronzing" or an ugly- looking grey will be the result. 



34 o LEATHER MANUFACTURE. 

After the skins are dyed a fine deep black they are well 
rinsed through a tub of cold water, horsed up, and 
allowed to drain. 

An American authority gives the following method of 
combining fat-liquoring and black dyeing in the drum. 
The black is composed of warm logwood liquor, in which 
5 lbs. of gum arabic are dissolved, whilst 8 lbs. of 
copperas are dissolved in another vessel. The gum and 
copperas solution are then mixed with 25 gallons of 
strong logwood liquor. When the skins have received 
the fat-liquor the black liquor is added to the skins 
whilst the drum is in motion, which is then run for 
another five minutes ; the skins are then washed in cold 
water and struck out in the ordinary way. 

Putting or Striking Out. — At this stage the skins 
are put out or extended by machine, the machine shown 
on Fig. 73, with the vertical rising table, being the 
most suitable. During the last year or two, however, a 
new machine has been on the market for the purpose, 
for which a much greater output of work is claimed. 
This consists of an arrangement by which four tables 
are kept in motion on the one machine, and under certain 
conditions it answers well, although some users allege 
there is hardly time for proper spreading, feeding, and 
taking off the skins. 

The skins should at this stage be struck out moder- 
ately tight and laid out flat, grain side up, when they are 
given a light coat of equal parts of glycerine and water, 
spread on with a suitable wad of some soft material or a 
sponge. 

In this condition the skins remain for a few hours, and 
are then reset or again struck out. This time they 
should be well extended, and all rough and uneven 
grain removed if the final surface is to be smooth and 
fine. 

Oiling and Drying. — The struck-out skins are then 
taken to a warm room for preference, and a coat of oil 
applied to the grain side. This should be of the best 
quality, and if reliable neatsfoot is to be had it is, perhaps, 



CHROME LEATHER MANUFACTURE. 341 

the best all-round oil for the purpose. There are, of 
course, other good oils on the market, but the damage 
likely to be caused in the leather by unsuitable oil is so 
great that any new oil should be at first experimented 
with only on a very small scale. 

The oiled skins are next dried out in a heated chamber. 
Opinions differ as to the efficacy of sharp drying, but the 
belief is common that the quicker the drying the less 
likelihood the oil has of either setting on the grain side, 
or of " spueing " up to the surface on the finishing stages, 
or even in the finished condition. As a matter of fact, the 
amount £>f drying room required is so great in a glazed 
leather works of any size that it is impossible to find space 
enough to dry slowly, although it is always a good plan 
to allow the drying chamber to cool down before the 
goods are taken out. The method usually followed is 
to stretch the skins out by the hind shanks on parallel 
racks studded with sharp tenter-hooks. The work should 
be so arranged that the skins are left to dry during the 
night, and taken down in the morning, when they are 
comparatively cool. In this condition the skins may be 
stored for some time, and should improve with age, 
although this ageing process is not as necessary as is the 
case with alum-tanned leathers, which used often to be 
kept for six months before finishing. 

Glazed Kid Finishing. 

Staking or Softening — The first operation in the 
finishing of glace kid is to well soften the leather; the 
process is known as staking, and is now almost always 
done by machine (see Fig. 75). The name of the pro- 
cess is derived from the fact that formerly it was done by 
pulling the skin over an upright wooden stake, into 
which was fixed a fairly sharp metal plate. In the early 
days of glace leather making the workman used his knee 
as well as his hands for the purpose, the operation being- 
known as knee-staking. 

To bring the skins into the right condition for staking, 
they are covered for a few hours with damp sawdust and 



342 LEATHER MANUFACTURE 

are then taken to the machine The principle of the 
staking machine is simple, the leather being extended 
and worked by a blunt knife, the jaws of the machine 
opening and closing by an ingenious mechanical arrange- 
ment. The work is, however, rather tiring, as the pull of 
the staking knife has to be neutralized by the pressure of 
the operator's body. Goat skins are usually staked 
twice, once from neck to tail, and once " to the breath." 
Care should be taken to see the shanks are opened out and 
a good pattern given to the skin. Some tanners still 
have their skins knee-staked after one machining, whilst 
others have them sorted over, and any which seem at all 
hard, worked over with a moon-knife or arm-stake. The 
cost of hand work, however, is so great, that only in few 
instances is it followed out, and it will probably soon 
disappear altogether. If the skins are very fleshy after 
staking they should be lightly fluffed on a wheel covered 
with fine emery powder, but as a rule a good stiff brushing 
on the flesh is sufficient before they are passed on for 
trimming. This consists of removing the edge rags of 
the skins with a pair of strong shears, and is quickly and 
cheaply done by girls or women. 

Seasoning. — -The softened and trimmed skins are then 
prepared for glazing by being wiped over on the grain 
side with a mixture known as a " season." This usually 
consists of blood or albumen solution, to which is added 
colouring matter in the shape of logwood decoction, ink, or 
black aniline dye. It is a mistake to give the leather too 
much seasoning ; the idea should be simply to bring the 
leather into condition for the subsequent glazing process. 
Many seasons are sold ready prepared ; but for the benefit 
of those who prefer to make their own, the following will 
be found useful : — 

6 qts. logwood liquor ; 

2 „ ox blood ; 

\ pt. orchil ; 

2 pts. water ; 

\ „ ammonia ; 

\ „ milk. 



CHROME LEATHER MANUFACTURE. %$% 

Another — 

5 gals, logwood liquor ; 
5 ozs. copperas ; 
\\ pts. blood ; 
5 ozs. glycerine ; 
8 „ ammonia. 

In many factories girls are employed for the seasoning, 
and their nimbleness and lightness of touch makes them 
very suitable for the work. In summer time the addition 
of some cheap antiseptic, such as phenol (carbolic acid), 
will keep the seasoning from becoming offensive. The 
season should be spread evenly and lightly with a soft 
pad and the skins hung up to dry. 

Glazing. — This being practically the last operation care 
must be taken to render it effective. Glace goat glazing 
may be called a skilled business : in any event, the pro- 
portion of bad work makes it an expensive matter to teach 
operatives the process, and none but those of a high order 
of intelligence should be employed. 

A good deal depends upon the machine used for 
the purpose, and the one in general use is known as 
the " Bower." This is built almost entirely of wood, the 
pressure of the glazing-glass being regulated by a foot 
lever and a rocking arrangement fitted with springs at 
the head of the machine (see Fig. 79). 

Iron machines, such as the type shown at Fig. 78, give 
great satisfaction for the heavier leathers, such as box- 
calf, &c. ; in fact, some tanners use them for the first 
glazing of kid, but taken all round the wooden " Bower," 
by reason of its resiliency and cheapness, is the best 
appliance for the glace leather maker to put into his 
factory. The work, however, is rather trying, as the soft 
leather has to be "humoured" to the work with the 
hands, whilst in the case of the old-fashioned stiffer 
leathers, like levant, the leather stood out boldly under 
the pounding action of the polishing tools. Good super- 
vision pays in glazing, and new beginners should only 
be entrusted to do common goods for the first glazing. 



344 LEATHER MANUFACTURE. 

After the skins have been glazed once they are then 
again lightly seasoned, hung up to dry, and glazed the 
second, and, if necessary, the third time. This practically 
completes the process, although it is an advantage in 
some cases to wipe over the grain with a clean oily rag. 
This helps the finish to stand moisture and handling- 
better, and slightly softens the leather, but is optional, 
and is not followed out in many factories. 

This, then, is the end of black glace or glazed goat 
manufacture. Enough has been said to give readers a 
good idea of the process, and given good skins, material, 
machinery, and skilled supervision, a saleable article may 
be made by following out the directions set forth. 
Mention should be made, however, of the fact that even 
after the leather is made, the chances of commercial 
success are much improved by careful measuring and 
grading the skins into the proper classes. Goat skins 
vary greatly in size, substance, texture, and fineness of 
grain, and the selection and grading is a work only to be 
found out by exrjerience in the markets catered for, and 
should be done by trained sorters, or by the principal 
himself, who fully realizes the responsibility of this final 
operation. 



Dyeing Fancy Shades on Cheome Goat. 

Before passing on to a brief review of the processes in 
vogue for chroming box-calf, &c, it would be well to 
give a few hints on the treatment of chrome goat skins 
which are intended for colouring. As before mentioned, 
the skins are sorted in the " blue " condition, i.e. after 
they have been struck out from the final washing after 
chroming. The dyeing is usually carried out in the 
drum or paddle, solutions of aniline dyes being used for 
the purpose. Methods differ a good deal, but the writer 
has found the following to give good results. First, 
mordant the skins in a weak solution of some tannin. A 
mixture of cube gambier and fustic extract of about 5 



CHROME LEATHER MANUFACTURE. 345 

per cent, of the wet weight of the skins, with enough 
water at about 140° Fahr., will produce a good foundation 
for most of the ordinary shoe colours. Sumac extract is 
also useful for the same purpose. These materials should 
be carefully dissolved and the skins drummed in the 
solution for about twenty minutes. The skins are then 
either drained or lightly struck out and fat-liquored. In 
some cases the fat-liquoring is done after the dyeing, but 
if the liquor is at all alkaline, the colour is stripped more 
or less, and often a nondescript sort of shade is the result. 

The hot fat-liquor is, as in the case of black skins, 
added -to the drum whilst the goods are in motion, the 
quantity being less, however, and regulated to suit the 
requirements of the particular sort of skin under treat- 
ment. After the fat-liquor has done its work the surplus 
water is run off and the dye liquor added. The writer, 
in actual practice, found it an advantage to take the 
skins from the drum, and to fold them straight down 
the ridges with the grain outwards. About one-third of 
the hot dye liquor is put in the drum, the skins quickly 
entered and the drum started, and the remainder of the 
dye added in successive portions. The time occupied by 
the dyeing is about a half to three quarters of an hour. 
Although both the basic and acid colours may be used 
for dyeing chrome leather, the acid range is preferred 
by many, especially where the water is hard. There is a 
wide range of these latter, and excellent shades can be 
obtained by a mixture of acid yellows, brown, &c, shaded 
with a little blue or green. The amount of dye required 
of course varies, but from 3 to 6 ozs. per dozen goat skins 
is usually sufficient. An American authority says that 
chrome tanned skins may be very satisfactorily coloured 
with sulfamine dyes, which require no mordant, and pro- 
duce full, clear, and uniform shades of colour. 

In dissolving the aniline dyes care should be taken to 
see they are well strained through a fine muslin cloth 
before the solution is added to the skins in the drum, 
otherwise the undissolved particles are apt to get on the 
grain of the leather and cause unsightly blotches. 



346 LEATHER MANUFACTURE. 

Much space might be taken up with a variety of so- 
called formulae for dyeing, but in the writer's opinion this 
would be of little practical value, owing to the differences 
in the requirements of the market, the uncertainty in the 
nomenclature of the dyes, and the various methods of 
working. Most of the aniline dye manufacturers keep a 
special range of colours for chrome leather, and are, as a 
rule, only too glad to furnish what information they can 
on the subject. Mention, however, might be made of a 
new dyeing process by what are known as the Corichrome 
mordants. These have been put on the market by the 
Chemische Fabrik Guestrow of Mecklenberg, the English 
agents being Messrs. W. and C. Pantin, 147, Upper Thames 
Street, London, E.C. These have been used with success 
on the Continent, and shades produced by the Corichrome 
mordants are said to be fast to light and almost fast to 
soap and alkali. No change is said to take place in the 
shade in the subsequent fat-liquoring in the drum — not 
even when an alkaline fat liquor is used. The shades 
themselves are actually determined by the Alizarine or 
fast mordant dye-stuffs used in the dye-bath (grounding- 
bath), and are perfectly developed by the subsequent 
treatment in the Corichrome developing bath (fixing-bath). 

There seems to be a great future before this method of 
chrome-leather dyeing, as it promises to do away with 
many of the difficulties, so far incidental to the process, 
which are many and formidable. 

After dyeing the skins are sometimes fat-liquored — if 
this has not been done before as just described — and, 
whethef fat-liquored at this stage or no, they are struck 
out, glycerined, reset, oiled and dried just as described 
for black glace. 

The finishing is much the same, but it is often necessary 
to " top-up " the grain with some fairly strong solution of 
colour, after the first staking, to produce the exact shade 
required. The " season " used, too, must obviously be 
different, and the writer has found nothing better for the 
purpose than a weak albumen solution, tinted with a suit- 
able dye. Dry albumen for the purpose should be left to 



CHROME LEATHER MANUFACTURE. 347 

dissolve in cold water, and kept sweet with a little dis- 
solved phenol. This should be made in a moderately 
strong solution, and diluted to the consistency required 
with cold water, and applied with a soft sponge or rag, 
carefully and evenly. 

The final staking and glazing is followed out in the 
same manner as described for black work, more care, if 
anything, being used to keep the skins clean and of even 
shade. Experiments, of course, should be on a small 
scale, and frequent tests made before deciding to put a 
large pack of valuable skins out for any particular shade. 



CHAPTER XXVIII. 

BOX-CALF MANUFACTUBE. 

Striking-out and Shaving. — Fat-Liquoring. — Dyeing Black. — Finishing 
Operations. 

The preparatory stages of chrome calf manufacture are 
much the same as for wax or kid calf, special care being 
taken to rid the pelt of lime, &c. For this reason the 
excrement pure or bate is often supplemented by wash- 
ing the skins in lactic acid solution, or the bran drench, 
the final scudding being also very carefully carried out. 
Some tanners also give the skins a pickle of acid and 
salt before chroming, claiming for this, that it makes a 
softer and fuller leather. About 50 lbs. of salt and 
about 5 pints of sulphuric acid dissolved in sufficient 
water is enough for one hundred skins, the skins being- 
pickled in about four to six hours, and the surplus liquor 
drained off before the goods are entered into the chrome 
bath. 

Salt is also often given the skins in the drum before 
chroming, or in the chrome bath, as it tends to keep the 
grain from becoming wrinkled and drawn in the process, 
and produces a softer leather. It also keeps the fibre of 
the pelt open, and helps the penetration of the chroming 
liquor. 

Calf skins may either be chromed by the two-bath 
method, as described for goat skins, or by what is known 
as the one-bath method. This latter greatly simplifies 
the process as it avoids the uncertainties of the chemical 



BOX-CALF MANUFACTURE. 349 

action incidental to the two-bath method. Various chrome 
liquors are now on the market, but the first one of any- 
great value was introduced by Martin Dennis, of America, 
and is still sold under the name of " Tanolin." Accord- 
ing to his original patent his liquor is obtained as 
follows : — First, a solution of neutral chrome chloride is 
obtained by solving a certain amount of chromic oxide 
in hydrochloric acid, care being taken that there is always 
a surplus of chromic oxide, i.e. there should always be 
more chromic oxide present than the added amount of 
hydrochloric acid is able to solve. To this solution 
caustic soda, or, better still, bicarbonate of soda, is care- 
fully added until a permanent precipitate of chrome 
hydroxide is formed. 

In this manner chrome-oxychloride or basic hydro- 
chloric chrome oxide is obtained, a compound easily 
soluble in water, which very easily parts with the super- 
fluous chromic oxide, especially in the presence of bodies 
possessing great affinity to chromic oxide ; for example, 
gelatinous hide substance. Besides chromic oxide the 
solution also contains common salt (sodium chloride), 
which is formed by adding the bicarbonate of soda to 
the hydrochloric chrome oxide. The presence of salt is 
of great use in the tanning process, as it prevents the 
swelling of the hides in the liquor, and helps to promote 
the tanning process. Very often more salt is added to 
the bath to ensure a good tannage. By these means a 
stock of tanning liquor is obtained which is suitably 
diluted before the skins are placed into same. The pro- 
cess is mostly carried on in paddles, beginning with a 
fairly diluted solution, and adding more of tne stock 
tanning liquor from time to time, until the skins are 
struck through a green colour in the thickest part. This 
process generally lasts from ten to forty-eight hours, 
according to the substance of the skins. The surplus 
of acid in the skins is neutralised by giving them a 
bath containing either calcium carbonate, lead carbonate, 
barium carbonate, or similar substances. 

A good formula published some time ago by Professor 



350 LEATHER MANUFACTURE. 

H. R. Procter is as follow : — Take 10 per cent, (of the 
weight of the skins) of chrome alum, and solve same in 
a sufficient quantity of water, and solve separately 1\ to 
3^ per cent, of soda. Add sufficient of the soda solution 
to the chrome-alum solution until a permanent precipitate 
of chrome oxyhydrate begins to form, and then add a 
small quantity of common salt. 

A writer in the Leather Trades Review states that he 
has also obtained excellent results from a chrome liquor 
prepared in the following manner : — Ten parts of chrome 
alum are solved in sufficient hot water, and the solution 
allowed to cool down, then a separate solution of three 
parts soda is made. Add sufficient soda solution to the 
chrome-alum solution until a permanent precipitate of 
chrome hydroxide appears, and then add lactic acid 
until the precipitate is just solved, and a clear liquor 
is obtained. 

With this solution make a fairly weak bath to start 
with, and, after allowing the skins to paddle for a couple 
of hours, add more of the chrome solution, continuing 
to do so at short intervals until the skins are struck 
through a greenish colour. The old bath may be used 
for a new lot of skins, and a new bath made into which 
the second lot of skins are placed when the first bath is 
used up, and so on. 

Amongst the various ready-made chrome liquors on the 
market the writer has heard that prepared by Prenzlau's 
Fabrikwerke, Hamburg, spoken well of. This is sold 
under the name of " Corin," and the following short 
description of the method of its application may be taken 
as being fairly representative. The skins are first placed 
into a 4 per cent, solution of " Corin," and are allowed to 
paddle, then more " Corin " is added at short intervals 
until all in all about a 10 per cent, solution is obtained, 
in which the skins remain until tanned. The Vacuum 
Oil Co., Ltd., York House, Norfolk Street, Strand, 
London, W.C., also sell a one-bath chrome liquor which 
has given great satisfaction to makers of box and willow 
calf. 



BOX-CALF MANUFACTURE. 351 

Generally speaking, all one-bath chrome liquors are 
sold in a highly concentrated form, and the makers give 
pretty accurate directions as to their employment, and 
in some cases even send out competent instructors to 
introduce them. 

Both the paddle and drum are used in box-calf tan- 
ning, the latter perhaps being, on the whole, the most 
convenient. After tanning, the skins are well washed 
in a borax solution of about 2 lbs. per cent, of pelt 
weight, and finally in clean water until they are free 
from salt and acid. 

Strifting-out and Shaving. — The skins are then well 
struck out, as described in the former chapter on glace- 
goat manufacture, and are now shaved. This is now 
almost always done by machine, and a good operator can 
do from fifteen to twenty dozen skins per day, if the 
leather is in good order, and does not require much 
reducing. Care should be taken to see the cutting- 
cylinder has suitable knives and is in good condition ; 
the grinding of the emery wheel should, as far as possible, 
be carried out when the skin is not actually under treat- 
ment, otherwise the particles of steel may cause trouble 
at a later stage, especially if fancy colours are to be 
produced. It is convenient after shaving to weigh the 
skins, as it furnishes a base for the calculation of the fat- 
liquor, &c, later on. Care should also be taken that the 
leather is not allowed to get dry, for it is impossible to 
damp chrome leather back, as is the case with vegetable 
tanned leather. 

The skins are often at this stage blue-backed in the 
drum, logwood, methyl violet, nigrosine, &c, being used. 

Pat-Liquoring. — This is done in much the same manner 
as already described for goat leather, the oily emulsion 
being added in a heated condition to the goods in the 
drum. Olive, castor, and neatsfoot oils are used in con- 
junction with various soaps, &c. Turkey red oil is also 
used, but probably the best all-round results are obtained 
from neatsfoot oil and egg yolk. The quantity of liquor 
given the skins varies a good deal, but averages from 



352 LEATHER MANUFACTURE. 

about 5 to 10 per cent, of the shaved weight. This, 
however, is a point best found out by experience. 

A good quality fat-liquor soap recommended by 
Professor Procter is made as follow: — 2 lbs. of caustic 
soda are solved in about 8 pints of water. This solution 
is poured into 20 pints of castor oil, previously heated to 
86° Fahr., continually stirring the whole time until the 
soap becomes thick ; after this, the tub containing the 
soap is covered and allowed to remain overnight in a 
warm place. The soap is now ready for use. It is as 
well, but not essential, to melt the soap again before use 
in a jacketed pan containing a stirring apparatus. By 
means of this apparatus a better and more even mixing 
of the soap is obtained. 

The following recipes for fat-liquors have also been 
collected and published by a writer on the subject : — 

1. One pint neatsfoot oil and 1 pint cod oil are stirred 
together with 1 pint of a 10 per cent, solution of soda, 
and this mixture is poured into a hot solution of 3 lbs. of 
soap chips in 6 pints of boiling water, continually stirring 
the whole time. Five to 10 per cent, of shaver's weight 
are then added to the necessary amount of water, i.e. for 
100 lbs. of leather (shaver's weight) about 10 gallons of 
hot water are taken. 

2. 4 lbs. of soft soap are solved in 1 gallon of boiling 
water, then add \\ lbs. of degras and f lb. of soda pre- 
viously solved in water. Five to 10 per cent, of this 
mixture is thinned with the necessary amount of water 
as above. 

3. 5 lbs. of soap chips are solved in sufficient boiling 
water, then warm 4 pints of neatsfoot oil, and stir same 
into the soap solution. Dilute the emulsion as above. 

4. Dilute 6 lbs. of soft soap in boiling water, then add 
5 pints of linseed oil to same, continually stirring until 
a good emulsion is obtained. Dilute same as above. 

5. 10 lbs. of soap chips are solved in boiling water, then 
add 4 gallons of neatsfoot oil, and 10 lbs. of egg yolk 
when it has cooled down sufficiently; stir until thoroughly 
emulsified, and dilute as above. 



BOX-CALF MANUFACTURE. 353 

6. Fifteen parts of olive-oil soap are emulsified with 
4^ parts of olive oil, and diluted as above. 

7. For fancy shades of colour the following fat -liquor 
has been recommended : \ per cent, castor-oil soap or 
olive-oil soap and f per cent, castor oil are stirred together 
until properly emulsified and diluted as above. 

8. The following fat-liquor is recommended by Jettmar : 
3 lbs. of castor-oil soap, 2£ lbs. of glycerine, 1£ lbs. of 
castor oil emulsified with 10 pints of boiling water. 

Whatever fat-liquor is employed, it should be added 
warm to the goods in the drum whilst in motion, a fresh 
liquor being either made by boiling it under a steam-pipe 
or by mixing in an emulsifier. 

The liquor is best added by a suitable arrangement at 
the side of the drum, which allows it to go through the 
hollow axle. If the drum is warmed up, so much the 
better, and it will be found that practically the whole of 
the fatty matter of the liquor will have been absorbed in 
about twenty minutes to half an hour. 

Dyeing Black. — After fat-liquoring, the skins are dyed 
black, much the same process being used as that described 
for glace goat. The skins are folded grain out from head 
to tail, passed first through a strong warm logwood de- 
coction, and then quickly through a black or iron striker. 
A good striker consists of 5 lbs. of copperas and 1| lbs. of 
blue vitriol dissolved in 20 gallons of boiling water. 
This is made up to 40 gallons, and about \ lb. of ground 
nut-galls added. The following iron blacks have also 
been published by an experienced writer on the subject : — 

1. Solve 10 lbs. of iron vitriol (copperas) in 8 gallons 
of water, and then add sufficient ammonia until a greenish 
precipitate begins to form ; add acetic acid in small 
quantities until the precipitate vanishes, and a clear yellow 
solution is obtained, which, when applied to the skins 
with a brush, will give a fine deep black. 

2. A cheaper black is obtained by filling a barrel 
three-parts full of old hoop iron, which should be devoid 
of rust, adding about 4 gallons of water and about 4 pints 
of vinegar. Place the barrel in a warm place, and after 

2 A 



354 LEATHER MANUFACTURE. 

about ten days fermentation sets in, which may be noticed 
by the froth which collects on the surface. The froth 
should be removed from time to time, and in about three 
weeks' time the black is ready for use. Before applying 
it to the skin, about equal parts of stale beer should be 
added to the black to thin it down. 

3. Another good black is obtained by solving 4 parts 
of iron vitriol and 1 part of copper vitriol (sulphate of 
copper) in 20 parts of water, and adding 3 parts of stale 
beer. 

The blacking process may also be done by brushing 
the solution on the skins, which are sleeked out on a table, 
or the black may be given in a tumbler. A good deal 
depends on the general arrangement of the work, and no 
definite rule can be laid down. Some manufacturers 
claim good results by the use of aniline blacks, and it is 
certain there is not the tendency to brittle grain, such as 
occurs at times with the iron striker on black goods. 
Others state the iron striker gives the best all-round 
results ; but the operation should be conducted by a 
skilled dyer. If aniline blacks are used for blacking 
after fat-liquoring, a little acetic acid must be added to 
the dye solution until it is slightly acid. This will 
counteract the effect of the alkali given by the fat-liquor 
soap to the liquor. In dyeing chrome calf in a tumbler 
a 1 to 1^ per cent, solution of the aniline black is given, 
and 2 to 3 per cent, of salt added. The temperature 
should be kept up to about 140° Fahr., the time occupied 
being about half an hour. 

After the skins have been dyed, they are carefully 
rinsed in water, and set or struck out by hand or 
machine. They are then given a coat of warm neatsfoot 
oil on the grain side, and sharply dried in a heated 
chamber. Many tanners prefer to strain the skins out 
on wooden frames before drying, and doubtless this 
gives a better measurement, and preserves the pattern 
on the skin much better than would otherwise be the 
case. 

Finishing Operations, — When the skins are dry they 



BOX-CALF MANUFACTURE. 355 

are taken to a cool room and allowed to lay for a few days 
until they are wanted. They are then slightly damped 
by being covered with moist sawdust, and staked. The 
method and machine used for the purpose is much 
the same as that described for glace goat. The work, 
however, is harder, and a good deal of judgment has to be 
used to avoid over-softening the flanks and bellies of the 
skins. The skins are then hung up and dried slightly, 
and restaked, after which the edges are trimmed with 
sharp shears. 

Box-calf is then given a seasoning, i.e. some suitable 
solutionis rubbed on the grain to prepare it for the sub- 
sequent glazing. Nearly every tanner has his own formula 
for the purpose ; but the following will be found reliable : 
6 ozs. of nigrosine dissolved in 5 gallons of water ; add 
2 pints of bullock's blood, 5 ozs. of glycerine, and 8 ozs. 
of ammonia. 

Another recipe : 5 ozs. of copperas are dissolved in 
5 gallons of logwood liquor ; add to this 2 pints of blood, 
5 ozs. of glycerine, and 8 ozs. of ammonia. 

A good formula used with success on the Continent is 
as follows : Beat up the white of three eggs, and then add 
2 pints of logwood solution ; well strain, and add 1^ pints 
of ox blood and J pint of milk. Weak solutions of albu- 
men and linseed decoction are also sometimes used, these 
latter, however, being more suited to seasonings for fancy 
colours, where the above materials are not suitable. 

In seasoning, only sufficient of the mixture should be 
applied to the grain with a suitable pad to enable the 
glazing to be executed properly, otherwise the latter 
process will not be a success, whilst the excess of season- 
ing is likely to peel off in the subsequent boarding. 
When the season has properly penetrated, the skins are 
then glazed by machine. There are several types in use, 
and each make possesses useful features. The pressure 
used in glazing must not be too great, otherwise the 
glazing glass is apt to leave marks on the skin which are 
difficult to remove. 

After the first glazing is complete, the skins are grained 



356 LEATHER MANUFACTURE. 

by means of the ordinary cork-covered pommel or arm- 
board. In box-calf it is usual to grain two ways only, 
once from the head to the tail, and then from belly to 
belly. It should be noted, too, that it is often advisable 
in the case of coarse flanky skins to lightly emboss with 
a suitably engraved roller before graining ; this prevents 
a coarse, unsightly " break," but only sufficient pressure 
should be used to assist the formation of the natural 
grain, as an artificial-looking break is strongly objected to. 

After graining, the skins are again seasoned lightly ; 
care should be taken the season is not applied too strong, 
and a shank should be tested once or twice before season- 
ing the whole lot, and the season modified or weakened to 
suit requirements. After the second seasoning a second 
glazing is given, first with a fairly heavy pressure, and 
finally with just sufficient pressure to remove the tool 
marks, streaks, &c. A final light boarding or graining 
completes the process, and after the skins have been 
sorted into qualities and sizes, the goods are ready for 
the market. 

In conclusion, it may be added that methods in vogue 
vary a great deal, but if the above directions are followed 
out, and practical common sense applied where modifica- 
tions are necessary, there is no reason why a good saleable 
article should not be turned out. The chrome process, 
however, requires constant attention to get uniform 
results, and experiments on a small scale are advisable 
until success can reasonably be anticipated. 



CHAPTER XXIX. 
CHAMOIS, OR OIL-LEATHER MANUFACTURE. 

Preparation and Frizing. — Drenching. — Stocking or Milling in Oil. — 
Pressing and Washing. — Finishing. — Chamois Glove Leather. — 
Bleaching. — Tucking.— Colouring. — Buff Leather. — Liming.— Pre- 
paring and Milling.— Scudding and Wash-house. — Buck Skin Dress- 
ing. — Milling or Stocking. — Scudding and Wash-house. 

The manufacture of "chamois," or oil-leather, is still 
one of the most important branches of the leather in- 
dustry, and an enormous home and export trade is done 
in this material. The preservative or tanning principle 
is not well understood, but it probably depends upon an 
oxidation of the fats with which the raw pelt is treated. 
It should be mentioned that oil tanning is one of the 
oldest methods known in the preservation of animal 
skins, and is still practised to this day by savage races. 

Chamois leather is now usually manufactured from the 
flesh splits or " linings " of the sheep skin, whilst white, 
or " buff " leather, '"formerly used so extensively for 
military accoutrements, is made from heavier hides by 
the same process with slight modifications. The manu- 
facture of chamois is mainly in a few large hands, as the 
plant is rather expensive, and the amount of capital re- 
quired considerable. Most tanners utilize the entire sheep 
skin, the grain side being tanned with sumac and sold 
under the name of "skiver" for a variety of cheap pur- 
poses, whilst the flesh split is either turned into chamois 
or " pickled " with sulphuric acid and salt for export as 
the position of the market demands. 



358 LEATHER MANUFACTURE. 

Sheep skins are first de-wooled by the fellmonger, and 
eventually collected by the dresser, who sorts them 
for the most suitable purposes. Those intended for 
splitting are given a further liming to plump them, and 
are then split on a machine with a rapidly vibrating 
knife. Assuming the flesh splits are to be dressed as wash 
or chamois leather, the process is as follows : — 

Preparation and Prizing. — After splitting, the linings 
are again put into lime, the lime-pits being so arranged 
that the solutions are of a gradually progressive strength. 
The goods are drawn frequently and the lime strengthened 
as required. This stage of liming usually lasts from ten 
to fourteen days, according to the class of skins and their 
condition. The linings are at the end of this time firm and 
in good condition for frizing, and all rough flesh and 
roughness can be easily removed with a sharp knife on 
the beam. Unskilled labour is often utilized for this 
purpose, and the operation is also done by machinery ; 
but it is doubtful if much real saving is effected. Skins 
badly frized are said to require more oil and to want extra 
work in the grounding operation. 

Drenching. — This process is usually carried out in tubs 
or vats, although in some of the larger works the drum or 
paddle is used. According to a writer in the Leather 
Trades Review, the tubs used are from half to two-thirds 
filled with water at a temperature of about 70° to 80° 
Fahr. To this water is added one to one and a half 
buckets of scalded bran or meal, the bucket reckoned as 
holding about three gallons. Previous to drenching, the 
skins are well washed, either in a drum or paddle, through 
which an abundant supply of clean water is kept running. 
This will free them from surplus lime and other objection- 
able matter, and show a saving in the amount of bran 
required. The skins are then placed in the drench tubs 
and are continuously stirred, though it is much quicker 
to use the paddle for the purpose. This will accomplish 
the deliming or drenching process in about six hours, 
against twelve to twenty-four required in the tubs. No 
definite rule can be laid down as to the amount of 



CHAMOIS, OR OIL-LEATHER MANUFACTURE. 359 

drenching required, but an experienced workman will be 
able to tell when the process has been carried far enough 
by the feel and general appearance of the skins. 

When the skins have been drenched, they are well 
pressed to remove surplus moisture and grease. This is 
usually done in an hydraulic press, the skins being 
arranged between plates, sacking, and wood blocks, the 
whole process taking about an hour. 

Stocking or Milling in Oil. — When the skins are ready 
for milling or stocking — the process being done in the 
machine shown at Fig. 6 (page 111) — each skin is well 
shaken -out to get rid of adhering bran or meal, and they 
are allowed to cool by being thrown on the floor, care being 
taken to avoid getting them dirty. They are then stocked 
for about an hour to get them in uniform condition. 
Then they are taken from the stocks and a three-gallon 
pail of cod oil is got ready, also a sprinkler made of 
heather sprigs. With this, one operative sprinkles 
the skins, whilst another gradually throws the skins 
into the stocks until sufficient oil has been given. They 
are then milled for three or four hours, when it will 
be found the skins are covered with soap, and will also 
have a soapy, slippery feeling when handled. The 
skins are now drawn from the stocks and taken to the 
sheds for air-drying, no artificial heat being applied at 
this stage. 

After about a day's steady drying the skins are again 
stocked and sprinkled with oil as before, the time being 
usually three hours. They are now drawn and stoved at 
a temperature of about 100° Fahr., the operation resulting 
in making the skins a brownish colour. This process 
of stocking and drying is repeated several times, until 
the final heating off, when the skins are hooked by the 
neck on ranges very closely in the drying stove. In this 
stove the heat is raised to about 150° to 160° Fahr., when 
a sharp, astringent odour will be given off. 

The skins are then thrown, whilst in the heated con- 
dition, in bins or casks, well trodden, and covered with 
sacking to retain the heat. The temperature will at once 



360 LEATHER MANUFACTURE. 

begin to rise, and the skins will require most careful 
attention. The millman should go frequently from bin 
to bin and note the temperature. At intervals they are 
turned by casting them into another bin, the workman 
using gloves for the purpose, and the goods well trodden 
down by a lad. This is repeated until the skins are 
heated off, a point only indicated by experience. 

Care should be taken that there is no surplus oil or 
moisture on the goods, or damage is very likely to result. 
The workmen should also wear goggles to protect the 
eyes, as the vapour arising from the skins is irritating. 
Sufficient goods should be always available to keep up 
the process of heating, otherwise parts of the leather will 
remain green, and will become drawn when treated 
with the alkalies later on. When the goods have 
assumed a characteristic dark-brown colour they are 
spread around to cool, and are ready for pressing and 
Avashing. 

Pressing and Washing — The skins are then thrown 
into a vat of water at a temperature of about 110° Fahr., 
and well pressed in the hydraulic press. Grease will soon 
begin to exude, and, later on, the substance known as 
sod oil, all of which being valuable, is carefully collected 
and treated further if necessary. 

When the skins are sufficiently pressed, they are then 
well washed in an alkaline solution prepared as follows : 
For ten dozen skins, dissolve 4 lbs. of soda ash and 2 lbs. 
of soda crystals in sufficient water at a temperature of 
120° Fahr. The washing is often done in a paddle, about 
twenty dozen skins being paddled for about two hours. 
The goods are now wrung out and the liquor run 
away. Fresh water is then run in the paddle and the 
heat raised to 130° or 140° Fahr., and the skins given 
another hour's washing. In most places some arrange- 
ment is made to save the liquor — the first being especially 
valuable — as this contains emulsified fats which are 
worth recovering. 

Wash-leathers may either be dried after the second 
washing or given a further liquor to improve their 



CHAMOIS, OR OIL- LEATHER MANUFACTURE. 361 

pliability. A practical writer on the subject gives the 
following method of preparation : Having run off the 
second liquor, make a third in paddle as follows : in a 
small mixer or tub put 10 lbs. of cod oil (about 1 gallon), 
add 20 lbs. of soft soap ; stir the two well together till 
the mixture becomes stiff, then add one gallon of boiling 
water until all soap, oil, and water are thoroughly blended. 
Take of this liquor 3 to 3^ gallons to the paddle of goods, 
and run for one hour ; then draw goods, take to either 
wringing machine or hydro-extractor. 

The skins are now taken to the drying sheds to be 
dried with air or artificial heat, being hooked by the 
two hind shanks on tenter-hooks from rail to rail ; when 
dry they are taken to warehouse, and are now called 
" crust " leather. 

For " fleshers," or heavier linings, the process is 
prolonged, and in washing the amount of materials 
is increased. 

Finishing; — In this condition the goods, as crust 
chamois, are often sold to dressers and others, who make 
a speciality of finishing for the market. The skins, after 
sorting into sizes and qualities, are first staked, either by 
the arm or upright stake, and are then levelled and 
worked out by the moon-knife on the perch ; this last 
operation being a skilled operation, and one requiring 
great care. The skin is extended in every possible way 
by the workman until it is thoroughly soft, and the fibre 
can be pulled in any direction. 

The goods when finished are then carefully trimmed 
with shears around the edges, and the holes, where 
possible, sewn up by hand or machine. They are then 
carefully sorted into qualities and sizes — the sorter 
stretching each skin as much as possible — and eventually 
put up into bundles of thirty, known technically as a 
"kip." These kips vary in price, some of them coming 
down as low as five shillings, whilst others may be quoted 
at fifty shillings. 

Chamois leather is almost universal in its application, 
being used by the tailor, the shoemaker for boot linings, 



362 LEATHER MANUFACTURE. 

the fancy leather goods maker, and for an endless variety 
of domestic purposes. A large export trade is also done 
in this material, America being one of the best customers 
of England, whilst Australia, Germany, France, Italy, 
and South America also take large quantities from our 
market. 

Chamois Glove Leather. — The stoutest and best skins 
are often sorted out in the crust condition, and finished 
specially for glove leather. They are first well grounded 
with a moon-knife on the side which is the most suitable 
for colouring. After this " paring " operation, they are 
then carefully run on an emery wheel to produce a fine 
smooth surface, when they are ready for bleaching. 

Bleaching.— In order to produce good clear colours on 
chamois it is necessary to bleach the leather. This is 
still done by exposure to light, the process taking two or 
three days in summer and as many weeks in winter. The 
skins are first well saturated with a warm solution of 
soapy water, made by dissolving a sufficient quantity of 
soft soap in it, and are then taken to a suitable grass 
plot, the side to be bleached and coloured being exposed 
to the light. This operation is repeated daily until the 
desired result is obtained, when the goods proceed to the 
next operation, known as tucking. 

Tucking — The skins are then thoroughly wetted 
through in warm water, and are then either wrung or 
run in a hydro-extractor, shook out, and hung on a suit- 
able wooden horse. Each skin is then separately immersed 
in a vat of boiling soapy water, and when sufficiently 
tucked, the skins are at once taken to a drying shed heated 
up to a temperature of 120° Fahr. When thoroughly dry 
they are taken to the stakers, who work the skins out 
either on the upright or by the crutch stake, when they 
are lightly gone over again on the emery wheel. The 
best size advised for this purpose is a wheel of about two 
feet nine inches wide by about nine inches in diameter, 
which should run at a good speed. 

Colouring.— Chamois skins are usually coloured one at 
a time by spreading them on a convex lead or zinc-covered 



CHAMOIS, OR OIL-LEATHER MANUFACTURE. 363 

table. The colour is usually of a mineral base, ochres 
and umbers being often used. Of late years more or 
less successful attempts have been made to use coal-tar 
colours, and in some hands good results are said to have 
been obtained. The usual mineral colour is mixed to a 
thick consistency in a sort of paint, and applied evenly 
with a suitable brush, care being taken to keep the 
colour well stirred. 

The leather is, after colouring, then dried off in a 
hot stove, cooled off in the air, and again staked. It 
is then well dusted or " beaten " over a heavy wooden 
stool to free it from dust, and again run over an emery 
wheel, care being taken the emery used is fine, so that 
the final appearance of the leather may be soft and 
velvety. 

The skins are now recoloured and dusted as before 
described, and in some cases the three operations involved 
are again carried out. 

Dark shades are often obtained on chamois leather by 
running the skins in a paddle or drum in a weak bark 
liquor or aniline dye, being subsequently, when dry, 
topped up or brushed over with a weak solution of aniline 
colour. 

Deep shades of brown are also at times obtained by 
hanging the skins in closed chambers, and subjecting the 
leather to the action of ammonia gas, generated by first 
running chloride of ammonia solution into a suitable 
vessel in the chamber, and, later, hot lime liquor to 
liberate the ammonia. 

Buff Leather. — Although buff leather has been to 
some extent discarded for British army accoutrements, 
yet a fair trade is still done in this material. Hides 
of a suitable class are used for its manufacture, the 
general principle being much the same as in chamois 
leather. According to a practical writer on the subject 
in the Leather Trades Beview, the process is as 
follows : — 

Liming. — The hides are put into old or weak limes at 
first, handled daily, and the strength of limes increased 



364 LEATHER MANUFACTURE. 

for about ten days, when it will be found the hair and 
cuticle can be removed by pushing over beam with 
unhairing knife. After unhairing they are put into fresh 
and stronger limes for a few days, which makes the hides 
firmer, when they are taken to either splitting or frizing 
shop. 

If split only a thin or light grain is taken off, or if 
frized the grain is only just taken off, as the flesh part of 
hide only is used in making buff or oil leather. After 
frizing, the goods are again returned to the lime-pit for a 
short time until ready for milling. 

Preparing and Milling. — The hides are drawn from 
the pit, and in place of being drenched are hung out on 
lines to partially dry out the water in them, by action 
of sun and air in summer, or in winter dried in a warm 
atmosphere. The reason they are not drenched is be- 
cause a firmer leather is required. When sufficiently 
dry they are taken to the stocking mill. On arrival 
at the mill they are thrown into stocks and milled for 
about two hours to distribute the moisture evenly and 
to soften them, as they have become hard or horny in 
drying. 

They are now drawn from the stocks and laid out to 
cool. Meantime, to every 3 gallons of cod oil, 1 quart of 
freshly sifted slack-lime is added, and the mixture well 
stirred. The hides are now thrown into the stocks, whilst 
another man sprinkles them with the mixture of oil and 
lime. After the stocks or fallers are full, run for three to 
four hours, when it will be found the hides are covered 
with a kind of lime soap, and have become warm by 
the constant beating. 

The hides are now drawn, and taken and hooked in a 
warm stove of a normal temperature, fitted with a blast 
fan, until sufficiently dry. This oiling and milling- 
operation is repeated several days, also the drying, but 
gradually increasing the warmth of stove each time, until 
the final milling preparatory to heating off. As the 
hides cannot be packed into tubs or bins to heat off, they 
are hooked in a very hot stove with a large coke fire in 






CHAMOIS, OR OIL-LEATHER MANUFACTURE. 365 

the centre, or heated with iron furnace pipes laid on 
bricks about twelve inches from the ground and all round 
the stove inside, the furnace door being let into wall at 
exterior of wall of building. The latter is the better plan 
with pipes which get red-hot, as with the fire in the 
centre of the stove it is a very disagreeable operation to 
make up fires on account of heat and the offensive, 
irritating smell (acroclin) given off from the hides. After 
the hides are thoroughly heated off, i.e. when they are 
hard and dry and of a dirty brown colour, they are ready 
for washing. 

Scudding and Wash-house. — The hides on arrival in 
the wash-house are put into vats containing the following 
solution : To every hide 3 lbs. of socla ash and 1 lb. of 
soda crystals, with a sufficiency of water at a temperature 
of 112° Fahr. The hides are laid out flat in this vat for 
twelve to fourteen hours ; they are then drawn, and the 
scudder takes them in hand, who places them over a beam 
and well pushes and presses them to remove as much 
grease as possible. 

They are now returned to the washers, who have 
heated the liquor they were drawn out of, and also 
added another lot of soda ash and soda crystals. This 
is now put into the drum (when the temperature is 
about 120° to 130° Fahr.). The hides are now thrown 
in and run for about one and a half to two hours, 
when they are drawn and the liquor run off. This 
liquor, also that from the scudding beam, is worth 
saving. 

Another lot of liquor is then made up as follows : ^ lb. 
of soda ash and \ lb. of soda crystals with sufficient 
water ; raise temperature to about 130° Fahr. The hides 
are now drummed in this liquor for about one and a half 
hours, and are now drawn and put into a vat containing 
a fat-liquor in same proportions to number of gallons of 
water as in treating chamois linings. They are left in 
this liquor about an hour, and are taken to the drying 
shed, which is preferably heated with warm air distributed 
with a blast fan. 



366 LEATHER MANUFACTURE. 

When dry they are ready for bleaching and " tucking," 
which is carried out in the same way as in treating chamois 
linings. But as hides cannot be handled by grounders 
over a perch with a moon-knife, they are taken by 
grounders and put on emery wheels or special hide 
machines to put the fine smooth face on them. 

Buck Skin Dressing. — Buck or deer skins are limed 
exactly as hides, first for twelve to fourteen days to 
remove hair and cuticle. After sufficient liming they 
are ready for drenching, first washing in clear water 
to rid of surplus lime, then drenched with bran liquor 
and pressed to get rid of surplus liquor in the same 
way as in treating chamois. They are now ready for 
milling. 

Milling or Stocking. — The milling is carried out on 
the same lines as in milling chamois (no lime being 
added to the oil), but the milling is prolonged as the 
skins have the grain on, having been neither split nor 
frized, and it is better, even after buckskins are heated 
off, to let them lie about for some time to feed on the 
oil before taking to scudding or wash-house. 

Scudding and Wash-house. — The skins on arrival in 
wash-house are immersed in tubs or bins of hot water 
placed at side of press, and are now pressed in the usual 
way (as in pressing chamois). On removal from the press 
they are immersed in tubs holding about 30 gallons, a 
hot liquor having been made up with soda ash and lime 
at a temperature of about 112° Fahr. overnight. They 
are put in loosely, and are left in this liquor till the 
grain begins to almost rot, when the skins are drawn and 
placed one at a time on a narrow beam, the beam not 
being more than ten to twelve inches in width, when the 
scudder takes a very keen knife and pushes the grain off, 
only taking very narrow strips or shavings off straight 
down the skin from neck to tail or vice versa, and 
frequently shifting the skin ; hence the necessity of a 
narrow beam. After scudding they are ready for the 
final washing. The scuddings or shavings are worth 
saving, being rich in grease. 



CHAMOIS, OR OIL-LEATHER MANUFACTURE. 367 

The skins, having been immersed in strong alkalies in 
the scudding shop, do not require the second immersion, 
but are drummed with 30 lbs. of soda ash to each hundred 
skins in a sufficiency" of water at a temperature of about 
120° to 128° Fahr. After thoroughly washing they are 
fat-liquored, as in treating chamois. 

When dry they are finished off on emery wheels or 
buck machines in the same way as in finishing hides. 



CHAPTEE XXX. 
CUBBYING. 

The Scouring-kouse. — The Shop. — The Curriers' Knife. — Currying Kip 
Leathers. — Waxed Kip Butts. — Sorting and Bounding. — Soaking 
and Softening. — Be-tanning. — Drum-stuffing. — Setting. — Finishing. 
— Stoning and Starching. — Graining. — Waxing. — Top-sizing. — 
Currying Satin or Glove Shoe Leather. — Soaking and Splitting. — 
Buffing. — Blacking and Setting. — Finishing Satin or Glove Leather. 
— Levant Leather. — Soaking and Splitting. — Setting, Buffing;, and 
Embossing. — Blacking. — Seasoning and Glazing. — Oiling. — Curry- 
ing Various Leathers. Wax Calf Skins. — Calf Skins for Memel. — 
High Shoes, Black Grain. — Split Cow-Hides for Brown Bags. — 
Blocking Boot-fronts. 

The art of currying consists in dressing skins, after they 
are tanned, for the purposes of the boot and shoe maker, 
coach and harness maker, saddler, and others, by which 
they acquire the pliancy, smoothness, grain, and colour 
necessary for the important purposes to which they are 
to be applied. The operations of the currier are chiefly 
mechanical, and form a distinct branch of the trade. Many 
light leather manufacturers, however, combine the art of 
currying with the other branches of their business. The 
curriers' shop requires plenty of space, subdivided into 
many compartments, for carrying on the numerous pro- 
cesses connected with the trade. If possible, the lower 
part of the building should be devoted to those operations 
in which large quantities of water are required, as soaking, 
scouring, and cleansing the leather. 

The Scouring-house is supplied with a series of wide 
tubs, in which the leather undergoes a preliminary soak- 
ing ; there is also a large, flat, and smooth stone, about 
8 feet long by 4J feet wide, supported by woodwork or 
masonry, upon which the leather is scoured. This stone 
has a slight inclination, so that the water used in scouring 
may freely run off the table on the opposite side to that on 




CURRYING. 369 

which the workman stands. A block of sandstone, called 
the rubstone, from 2 to 3 feet long- and 9 or 10 inches wide, 
fixed on a trestle, is employed by the workmen for sharpen- 
ing their various tools. A finer stone, called the clearing- 
stone, is used to remove the marks produced by the coarser 
stone. 

The Shop, as it is called, is a light and generally spacious 
apartment, in which is the beam (Fig. 55) on which the 
leather is shaved. The beam is 
constructed of a stout block of 
wood, upon which the work- 
man stands, and into one end 
of which a strong- plank of 
hard wood is firmly secured, 
at an angle of 80° to 90°. The 
working beam is about one 
foot in width, and its height 
is regulated according to the 
height of the workman, each K 55> 

man having his beam adjusted 
to suit his convenience. On the face of this upright, as it 
is called, a piece of hard and perfectly smooth wood — ■ 
generally lignum nice — is attached, and which agrees with 
the edge of the knife used in the operation of shaving. It 
is of the utmost importance to the operator that his knife 
and beam should be in perfect order, otherwise the skins 
would be liable to injury from the irregular action of the 
tool. 

A series of tables, the plane surfaces of which are 
usually made from mahogany or marble, are firmly 
fixed to the floor of this apartment, near the windows, 
so that the workmen may have the full benefit of 
the light. At a short distance from each table, and 
behind the workman, is a wooden trestle, across which 
the currier throws each piece of leather after he 
has worked it on the table in any of the dressing opera- 
tions. There are many compartments in the currying- 
shop, each being devoted to some special branch of the 
business, and furnished with one or more tables and trestles., 

2e 




370 LEATHER MANUFACTURE. 

and the particular tools required for the operations to be 
conducted therein. 

The Curriers' Knife. — The most important tool is the 
curriers' knife (Fig. 56), which consists of a blade of 
fine steel, tempered in a peculiar way, 
and firmly riveted between two plates 
of iron. It is furnished with two 
handles, one of which is horizontal and 
the other vertical, the latter being 
Flg - 56 ' held in the left hand. The method of 

giving an edge to this tool, which is remarkable, is thus 
described by Ure : " This instrument is taken to the 
rubstone and ground to a perfectly sharp edge by succes- 
sively rubbing it forward and backward, care being taken 
to keep the edge true, that is straight. When this has 
been satisfactorily accomplished, it is still further rubbed 
on a Scotch or Welsh stone called the clearing -stone, until 
the scratches of the rubstone disappear. In this operation 
a fine thread or wire forms on the edges, for the knife has 
two edges, which must be carefully got rid of, after which 
it is wiped dry and the edges greased with tallow or oil. 
The workman then takes a strong steel, and placing him- 
self on his knees, he fixes the knife with the straight 
handle against any firm body and the cross handle between 
his knees ; then holding the steel in both hands, he care- 
fully rubs it forward and backward the whole length of 
the edge. During this operation the knife is gradually 
raised by means of the cross handle until it is nearly per- 
pendicular ; by this means the edge is turned completely 
over. If the knife is not well tempered the edge thus 
obtained will be irregular or broken, in either of which 
cases it is of no use whatever. To keep the instrument in 
proper order requires great skill on the part of the currier. 
The edge is so delicate and liable to injury 
O^^U^" that it cannot be used more than a minute 

or two without losing its keenness. To 
lg ' * restore this a very carefully prepared small 
steel is used (Fig. 57) ; the point of the steel is first run 
along the groove and then along the outside edge. 



CURRYING. 



371 



The knife is used as shown in Fig. 58. the operation 
here depicted being known as hand-shaving. The 
process is now often done by machine, which, together 
with the modern methods of currying, are now dealt 
with. 




Fig. 58. 



Currying Kip Leathers. — Whilst it must be acknow- 
ledged the old methods of currying produced a leather 
which proved serviceable in wear, experience has shown 
that its manufacture has lately produced little profit to 
the currier. The principles underlying the treatment of 
leather by the currier remain, it is true, much the same, 
but machinery has displaced hand labour to a great 
extent, whilst some processes have either been dispensed 
with altogether or very much shortened. It is only fair 



372 LEATHER MANUFACTURE. 

to say that the advance in leather manufacture is largely 
due to American initiative and enterprise, for our markets 
are flooded with cheap-dressed leather from the United 
States, whilst American machinery is being sold all the 
world over, and copied by competitors everywhere. 

The extent of the American trade in leather is clearly 
shown by a reference to official statistics, and it speaks 
volumes for the cheapness and excellence of the trans- 
atlantic product, if we remember that 515,686 cwts. of 
rough and dressed leather were bought in 1905 by Great 
Britain alone. The business is an enormous one, and it is 
obvious that, with such competition to face, the British 
currier has had to get into line with the American, and it 
is proposed to here briefly describe a few of the methods 
now in vogue in our more up-to-date leather works. Need- 
less to say, they vary according to the particular market 
catered for, or the fancy of the foreman or manufac- 
turer, but the principles are much the same, whilst the 
machinery employed is similar in large and small estab- 
lishments. As a chapter is devoted elsewhere to the 
consideration of modern leather manufacturers' machinery 
it will not be necessary to give needless details here, 
beyond just the points required to make matters under- 
stood. Since this book was first written, the causes alluded 
to above and the introduction and popularity of the chrome 
process have lessened the consumption of stout upper 
leather enormously. In fact, many go so far as to say that 
the total extinction of wax leathers, i.e. leathers finished 
black on the flesh side, is only a question of time ; others, 
it is true, do not hold this view, for wax leathers possess 
qualities which make them specially suitable for the 
heavy hard wear of the mechanic, agriculturalist, and 
other wearers who require a boot fairly waterproof, with 
a certain amount of porosity and at a low price. For 
these reasons, then, waxed leathers are still popular, but 
have to be produced at a much lower price than was 
formerly the case ; and it is proposed in this chapter to 
give an outline of the processes involved in the currying 
of kip butts, a leather which has even now a large sale. 



CURRYING. 373 

Kips, it should be said, are the hides of the native 
cattle of India; these are imported in enormous quan- 
tities both in the raw and partly tanned condition ; and 
to a large extent the prosperity of Leeds as a leather 
centre has been built up on the successful exploitation 
of this special trade. 

Waxed Kip Butts. — It will be more convenient for 
the purposes of discussion if we consider the kips here 
alluded to are those which are bought in the half- 
tanned condition by the currier. This leather is im- 
ported by merchants into England, and at intervals 
auction- sales are held in London, a sample of the 
goods being first inspected by the prospective buyer. 
The buying is mainly done by the buyers' broker, 
whose small commission is more than saved by his 
expert knowledge placed at his clients' disposal, whilst 
it is also an advantage that competitors should not 
know what other buyers are obtaining. The tanned 
kips are selected into qualities and weights and care- 
fully catalogued, and the buyer naturally selects the 
various " marks " and average which suits his particular 
trade. The larger buyer of Indian kips also purchases 
what are known as " original bales " direct of the im- 
porters, but as these hides run rather irregular in 
weight and substance, it is more economical for the 
smaller currier to buy the selected classes at the 
London sales. The character of the Indian tannage 
varies greatly with locality ; for instance, Bombay 
kips are clean and well got up, but somewhat spongy, 
whilst Madras are hard, and often badly plastered on 
the flesh side. 

Sorting and Rounding. — We will assume, then, the 
currier has obtained his kips, and that they are in his 
warehouse. The first operation is to sort for the various 
purposes required, throwing out all the badly-flayed and 
branded kips for levant or lining leathers, or any purpose 
where the perfect flesh side is not a sine qua non. After 
sorting, the kips are "rounded" or cut up into butts, 



374 LEATHER MANUFACTURE. 

shoulders, and bellies, the butts, as a rule, being the only 
part sufficiently compact in the fibre to make waxed 
leather. 

Rounding is a process requiring great care and 
judgment, and should only be undertaken by a man of 
experience. No two kips are exactly alike in growth, and 
it is easy to leave an inch or two on the offal which 
should have been allowed to remain on the butt, or vice 
versa. A rough idea will be gathered of the usual method 
followed out in rounding kips by an examination of the 
diagram shown in Fig. 14 (page 127). 

After rounding the kips the butts are carefully 
weighed and put up into " packs " or " lots " of about five 
dozen. It is needless to say that a proper stock or ware- 
house book should be kept of all lots going out, and that 
the warehouseman should, on giving out the goods to the 
currier for dressing, also give him the stock number, so 
that track may be kept of the leather right through the 
works to the finishing department. 

Soaking and Softening.— On receiving his "lot," the 
currier proceeds to soak or dampen down the leather ; it is 
important this should be done with care, otherwise the 
subsequent operation of shaving is rendered very difficult. 
The leather should be given just sufficient water, so that 
on doubling back the grain side, the moisture just oozes 
out. In very cold weather it is an advantage to soak the 
harder tannages of Indian kips in warm water. The 
Madras leather especially is usually undertanned, 
plastered with mud or grease on the flesh side, and so 
compressed by various methods that it is often difficult 
to get the leather to take the water at all unless it is 
warmed. Of course, it goes without saying that excessive 
heat must not be used, otherwise damage to the leather 
is the result ; but it is a pretty safe rule that if the work- 
man can bear his hands in the soak-tub, the water is not 
too hot for the leather. 

After soaking, the leather is usually allowed to lie in 
pile for a few hours, so that the moisture permeates 
evenly through the fibre. After this the kips are 



CURRYING. 375 

softened in a clrum-tunibler, no further water being 
added. This has the effect of taking the excessive stiff- 
ness or " bone " out of the leather, thus rendering the 
subsequent operation of shaving much easier. 

Before shaving, however, the butts are cut down the 
centre, and the two halves plainly marked on the grain 
side with the stock number and the " fellow mark." This 
is done so that the two halves may be matched up later 
on in the currying process. 

We now arrive at the shaving operation, which has 
been fully explained at the opening of this chapter. 
This important operation is, in many factories, still 
done by hand, i.e. by the use of the double-edged 
knife pressed smartly with a downward stroke on the 
flesh side of the leather over a sloping lignum vitce 
wood block (Fig. 58). The skilled kip-butt shaver levels 
to some extent the inequalities of the leather, and at 
the same time endeavours to pare out the veins, flaws, 
and other defects of the leather. The shaving must be 
free from knife-galls and scratches, the latter especially 
showing up in a very unsightly manner when the leather 
is finished. Generally speaking, the aim of the beams- 
man, or shaver, should be to produce a fine and even 
surface at the least possible loss of weight and appear- 
ance. 

The introduction of the splitting, and later the shaving 
machine, has, however, affected the art of the old crafts- 
man, and it seems only a question of time when the whole 
of waxed leather will be shaved by mechanical methods. 
Turning first to the splitting machine (see Fig. 54, page 
322, and Fig. 68, page 412), wonder may be expressed that 
this easy and cheap way of levelling leather has not long 
since superseded shaving for wax leathers. Experience 
has, however, taught that split leather does not produce 
so fine and dense a fibre as that obtained by hand shaving. 
It is true, kip butts are sometimes lightly split, but these 
are invariably re-shaved, or "flatted," to minimise the 
effect of splitting as much as possible. Still, where 
excessive fineness of face is not an absolute necessity, it 



376 LEATHER MANUFACTURE. 

is often advantageous and economical to take off a light 
split from the rump part of the butt, as it obviously saves 
both labour and material. No amount of work and 
material will, however, make a badly split kip butt equal 
in appearance and value to the shaved article, so that the 
operation, if done at all, must be done with great care 
and judgment. 

As may be gathered from the chapter on leather- 
dressing machinery, a good deal of shaving is now done 
by machine. In fact, practically all the lighter upper 
leathers which are finished on the grain side are now 
shaved in this manner, but it is still an open question in 
the minds of experts whether there is any great saving in 
the use of the machine on waxed goods. As a matter of 
fact, both hand and machine methods are in use by 
equally progressive concerns; but it is fair to say that 
some manufacturers of the very best waxed butts still 
favour the ancient method of hand-shaving. The 
objections urged by many against the shaving machine 
seem to be much the same as those experienced by split 
leathers. Still, the difficulties incidental to machine 
kip-butt shaving have certainly been overcome by some 
curriers who are turning out a good article. These 
leather manufacturers now sort out the various weights, 
and use different cutting cylinders to suit the substances 
required, and apparently the finished wax leather appears 
equal in every respect to the hand-shaved article. It 
seems, therefore, extremely likely that it is only a 
question of time when waxed leather as a whole will be 
shaved by machine, for continual improvements are being 
added, whilst the currier has profited by experience, and 
year by year more fully understands the capabilities of 
such profitable mechanical aids. 

As shaving machinery is more fully dealt with else- 
where, we will proceed to take our shaved butts to the 
next operation. 

Re-tanning. — As the butts are usually very under- 
tanned, it is necessary at this stage to rectify this, other- 
wise the leather will not take up sufficient grease, and will 



CURRYING. 377 

be deficient in solid fibre. Various metliods are in use ; 
some people lay the goods in pits with a strong tanning 
liquor for a few weeks, whilst others are content to give 
them a brief immersion in sumac liquor, or an hour or two 
in a good strong tan liquor in a drum-tumbler. In many 
large works the butts are well tumbled in a mixed tan liquor 
composed of gambier and sumac, and perhaps myrobalans, 
for six or eight hours. After this they are then again 
drummed with a sumac and gambier liquor strengthened 
up with sufficient good oakwood extract. After this 
second drumming the butts are washed through a warm 
sumac .liquor to brighten up the colour, and are then 
allowed to drain for a few hours, when they are hung up 
to dry. Various machines are in use for ridding the butts 
of moisture before drying. In some works the hydraulic 
press is brought into requisition, whilst others use a form 
of squeezing machine. It is by no means certain, how- 
ever, that these are an advantage for the purpose, as it- 
is thought by some that the loss of certain solid matters 
in the tannin leads to a loss of weight in the finished 
leather. 

In the olden days butts were after re-tanning scoured 
out flesh and grain on the slate table by means of 
sleaker and stock stone, when they were "sammied," 
or half-dried, thoroughly stretched or " set " out on a 
wooden or marble table, and stuffed on the flesh side by 
applying a liberal coat of dubbin by means of a brush. 
The butts were then dried out slowly, and then "tal- 
lowed " on the grain side, or, in non-technical language, 
rubbed over on the grain with a slight coat of dubbin. 
Hand-stuffing has, however, been almost entirely super- 
seded by a method known as drum-stuffing, by which 
melted fats are mechanically worked into the leather in 
the tumbler. This is really the most important modern 
development of the curriers' art, and as such warrants a 
full description of its technique. 

Drum-stuffing. — The successful application of grease 
to leather in the process of drum- stuffing depends upon a 
variety of conditions, and much money has been lost 



378 LEATHER MANUFACTURE. 

before the various points were fully understood. Even 
now burnt leather is fairly common, although the intro- 
duction of air-heated tumblers has greatly lessened the 
risks common to the use of steam for the purpose. The 
modern hot-air drum (see Fig. 70) is now often fitted 
with a grease melting and mixing pan, and is so arranged 
that the melted fats are fed automatically into the drum ; 
other tumblers are fitted with both steam and hot air, 
the former being useful for cleaning purposes. The main 
advantage about the hot-air tumbler is that it can be 
rapidly heated and cooled, the latter being often done by 
injecting cold air. 

To return, however, to the modus operandi of drum- 
stuffing. The butts, after drying, are first carefully 
weighed, and the amount of grease to be used calculated 
on a percentage of this dry weight. After weighing they 
are damped down again ; not too much water must be 
given, or the leather will fail to absorb the grease, whilst 
if the butts are too dry, the risk of burning is great. 
After the butts are quickly dipped in the water they are 
laid in pile for a day or two and carefully covered with 
bagging. This has the effect of allowing the goods to 
get into better condition, as the moisture becomes evenly 
distributed. At the end of this time the butts are 
slightly damped in the dry places with a brush, when 
they are ready for stuffing. 

A good deal might be written on the various materials 
employed in drum-stuffing, for since it was found hard 
greases, such as waxes, stearines, &c, produced a better 
looking and heavier leather, the old-fashioned tallow and 
cod oil have largely dropped out of the currier's list of 
materials. However, it will be sufficient for our purpose 
to give one or two representative stuffing mixtures and 
their method of application. Generally speaking, the 
firmer the leather is required the greater the proportion 
of hard grease, wax, or stearine given to it. In America 
it is known that as much as 80 to 100 per cent, on a dry 
weight of the leather is worked in ; but English curriers 
for various reasons do not, as a rule, obtain such results. 



CURRYING. 379 

In drum-stuffing the drum is first heated up to the 
proper temperature, say, about 130° to 140° Fahr., when 
the condensed steam in the form of water should be 
run off. 

In the older form of drum the melted grease was put 
in, and the damp leather stacked on the shelves, when the 
door was securely fastened and the drum set in motion. 
Another and better plan is to put the butts into the 
heated drum and allow them to run without grease for a 
few minutes ; this has the advantage of heating the 
leather through, so that when the hot grease is subse- 
quently added it does not coagulate on the surface of the 
leather and thus prevent its penetration. In the more 
modern form the grease is fed through the axle of the 
drum whilst it is in motion. This is a much better 
arrangement, as it prevents any single piece of leather 
sticking to the side of the drum and thus only getting 
partially stuffed. Kip butts should be run in the grease 
from thirty to forty minutes, after which the drum door 
is taken off and replaced by an iron grill or grate, and 
the goods allowed to run another half-hour to cool down. 
It is best, in order to get this result, to run the goods for 
a few minutes, and then to stop the drum for another 
short period, as this prevents the butts from being 
knocked about too much, and thus parting with a portion 
of the grease. 

As before hinted, no two curriers use precisely the 
same stuffing mixture, and a good deal of unnecessary 
secrecy is observed with regard to their composition. In 
the early clays, when drum-stuffing was introduced from 
America, nothing but cod oil and tallow was used ; now 
the number of greases used is legion. Good curriers 
claim often to get as much as 50 to 70 per cent, gain 
on the rough weight of kip butts by the use of such 
materials as stearine, degras, or sod oil, paraffin wax, and 
perhaps a little resin. The first mentioned is, of course, 
the chief constituent, and splendid results are obtained in 
quality and weight by the use of a stearine of about 
100° Fahr. melting-point. One good and representative 



380 LEATHER MANUFACTURE. 

stuffing mixture for kip butts is as follows : For 100 lbs. 
of dry leather take, say, 10 gallons of stearine — or, if 
tallow is used, say, 50 per cent, more — 1 gallon of sod 
oil, and 5 gallons of degras. 

It is, however, of little practical use to give other 
formulas for stuffing mixtures, as everything depends 
upon the tannage and the requirements of the market. 
A great deal must be left to the judgment of the in- 
dividual, but if the rules and methods given are carefully 
followed out no loss or difficulty should be experienced. 
Top much care cannot be given to the choice of good and 
suitable stuffing materials, and experiments should be 
carried out slowly at first, and on a small scale, as trouble 
with leather does not always make itself manifest until 
after the finished leather has laid in stock for some time. 

Setting. — This is an operation which has to be done 
quickly and thoroughly, so as to remove all stretch and 
contracted grain. The methods in vogue differ slightly, 
but as a rule the grain side is first well worked out on a 
fiat table with a stock stone, and the flesh side then well 
"canked" or extended with a suitable steel sleaker. The 
grain is then again stoned and glassed with a rounded 
glass in a suitable handle, and the butts hung up to dry. 
(Some curriers prefer to cank them first, and after stoning 
the grain allow the butts to slightly samm or dry, and 
then reset. Some lay them in pile between the two 
settings, and on the whole the best results perhaps are 
obtained this way if the damp butts do not lay too long 
and thus become heated. 

In any event, drum-stuffed leather should not lay 
about in the air long, as oxidation is apt to set in on the 
exposed surfaces and cause unsightly stains. Machines 
are now being used for kip butt setting, and once the 
technical difficulties in the way are overcome, it is only 
a question of time when hand setting will become 
extinct. 

Special stress has been laid upon the drum-stuffing 
process owing to its revolutionary character as compared 
with the old hand method, and also to the difficulty of 



CURRYING. 381 

obtaining reliable working data upon it. However, 
we will now assume our kip butts have been carefully 
dried in the sheds. If this has been carried out with- 
out the use of too much artificial heat, they should 
be of a good colour and not inclined to crack on the 
grain. If the grease has done its work, very little in 
the way of rounding or " tallowing " is wanted, although 
it is better to go through them and apply a little dubbin 
where it is required. Some curriers lightly brush over 
the flesh side with dubbin, and allow the butts to lie in 
pile for mellowing purposes for about a month. The 
butts are then ready for the final operation of finishing, 
and as there is practically no grease on the surface of the 
leather the old process of "making up" — necessary to 
hand-stuffed goods — may be dispensed with. 

Finishing. — Whitening is the first operation, and it is 
interesting to note that since this book was first written the 
whitening sleaker has completely ousted the light shaving- 
knife for that purpose. The sleaker is much more con- 
venient to use, and in skilled hands produces a better result, 
besides taking less weight off the leather. The work is 
now usually done on a glass or marble table, and if the 
butts have been properly shaved, it is only necessary for the 
workmen to just skim off the light nap or fibre which has 
been raised by the previous processes. The workman, by 
pressing the leather firmly against the edge of the table 
with the upper part of his legs, proceeds to take a bold 
sweeping stroke straight up the butt, and finishes up by 
lightly skimming over towards the belly edge. 

Whitening is greatly facilitated by first moistening 
the surface of the leather by a weak soap solution ; 
this is easily applied with a brush or sponge, and not 
only greatly assists the workman, but helps to form 
a fine and close surface. Good whitening is all- 
important, and the work should be free from scratches 
or " stabs," whilst every care should be taken to avoid 
cutting too deeply into the leather, otherwise coarseness 
of fibre is unavoidable. In most works the foreman 
carefully looks over the butts after whitening, casting 



382 LEATHER MANUFACTURE. 

out any which are badly done. Whitening is now often 
done by machine, and good results are obtained by 
the use of a special cylinder on the shaving machine. 
The machine shown at Fig. 72 is also used for the 
purpose. 

Stoning and Starching.— After whitening, the butts 
are stoned and sleaked over on the grain side to remove 
any adhering grease, &c, and are then often trimmed 
round the edges with a sharp knife to remove rough 
edges. The currier then mates each half butt with its 
proper fellow by examining the marks on the grain 
side of the leather made before shaving. The butts 
are also often buffed in places on the grain side if 
this has not been done before whitening; this is a 
great improvement to the commoner classes of goods, 
and removes scratches and broken grain, which, if left, 
look very unsightly. The butts may at this point be 
given a weak coat of some mucilaginous solution, to 
which is added a little colouring mixture, such as anatto 
or some suitable aniline dye. This operation is techni- 
cally termed "starching," although the solution used is 
generally composed of glue and water. After the butts 
have been hung up to dry, they are ready for graining. 

Graining. — This process is fairly simple as applied to 
kip butts for waxing, for, as a rule, the shoe manufacturer 
requires the leather firm, so that it stands up boldly in 
the boot. In most works graining is now done by cross- 
ing and recrossing the grain of the leather with a cork- 
covered pommel, the same tool being used for "bruising : ' 
or softening. The old hand-graining board is now only 
used for the lighter kind of leathers, such as sheep and 
goat skins, a heavier and much more serviceable tool, 
called the "arm board," being used for graining kip 
butts. 

Graining is so well understood that it is not necessary 
to again take up space by describing it ; the primary 
idea is to somewhat soften the leather, whilst the operator 
should endeavour also to develop a small neat figure, 
such as one is accustomed to see on grained calf skins. 



CURRYING. 383 

Naturally the workman pays most attention to the hard 
and close parts of the butts, as the less pressure put upon 
the belly and shoulder parts the better, owing to the 
comparative looseness of the fibre. 

At this point the leather is for all practical purposes 
well curried and ready for the final operation, although 
some curriers prefer to apply a light soap solution, which 
is well glassed into the flesh side before the butts are 
passed on to the waxing-room for the final blacking and 
sizing. In this state the leather is said to be "in the 
russet," and it is in this condition the famous French 
tannages of calf skins are exported, the final blacking 
being put on in England or elsewhere. 

■Waxing 1 . — Here, again, every waxer has his own par- 
ticular methods and ideas ; the principle involved is, 
however, very simple, the idea being to produce a good 
and deep black on the leather, with a modified gloss 
which will stand the somewhat severe handling of the 
shoe manufacturer. Some waxers use a sort of weak 
paint composed of cod oil and lamp-black, to which 
a little weak sumac liquor is added to facilitate matters, 
whilst others prefer a soap solution as a medium for 
the colouring matter. The soap colour is, perhaps, the 
most useful, as it helps to produce the great desidera- 
tum of the currier — a fine and smooth surface. With 
this colour, too, there is no d auger of darkening the 
leather, as is often the case when oil colour is used 
in a warm room by a waxer who is anxious to show a 
good grain of weight. But whatever colour is used 
only enough should be applied with a brush to give a 
good black, or it will be difficult to remove the excess 
of "smut" or solid matter. This is usually done by 
rubbing over the leather with the hand or a suitable 
brush, and is a very necessary section of the waxiug 
operation. After smutting, the butts are usually again 
glassed and are then bottom sized, i.e. given a weak coat 
of a properly prepared compound which is well rubbed 
in with a glass tool. The composition of bottom sizes 
varies greatly, but the following are practical, and if 



3»4 LEATHER MANUFACTURE. 

modified to suit individual cases will be found very 
useful : — 

1 lb. best glue ; 

1 „ flour ; 

8 oz. soft soap ; 

4 „ sugar of lead. 

The whole of the materials are first dissolved in seven or 
eight pints of logwood liquor, and incorporated by stirring 
during cooling. 

Another bottom size is prepared thus : — 

10 pints of logwood liquor ; 
1 lb. best glue ; 
1 „ flour ; 
\ „ soft soap ; 
^ „ sulphate of copper (" bluestone "). 

Whatever bottom size is used, care must be taken 
that it is used sufficiently weak, or trouble will certainly 
arise when the final top-sizing is given to the leather. 
In practice it is usual to first try both sizes experiment- 
ally, and weaken down with water or a little dubbin if 
found too strong. 

Top-sizing. — After the bottom size has been well 
glassed in and allowed to dry, the butts are then top- 
sized. Only sufficient should be given to nicely cover 
the leather, a special brush being used for the purpose. 
Atter the composition has been applied, a fine smooth 
surface is obtained by finally rubbing the still damp sur- 
face with a leather-covered pad or a bare arm, the aim 
being to obliterate the brush marks. The butts are then 
hung up in a heated chamber and allowed to dry. A final 
glassing and oiling with warm cod oil completes the pro- 
cess, and if the methods outlined have been followed out, 
a saleable article should be the result. If the sizing has 
been well done with suitable materials, the surface should 
improve with age, whilst the size should become tough, 



CURRYING. 385 

and possess a " bloom " which is appreciated by buyers 
of this kind of leather. 

Before closing this chapter it may be as well to give a 
typical top size for waxed leather. This may, as before 
hinted, want slight modifications to suit individual re- 
quirements, but it will be found a good working formula, 
and as such worthy of note : — 

1 lb. best glue ; 

10 pints of logwood liquor ; 

2 pints cod oil ; 
2 oz. beeswax ; 

6 shoe-finishers' heel-balls. 

The glue is first soaked in a part of the logwood liquor 
and then slowly dissolved by heat ; the other ingredients 
are also dissolved in a separate vessel and added to the 
glue solution ; both solutions should, of course, be first 
carefully strained through a fine muslin cloth. Care 
must be taken to keep the size stirred during the cooling 
process, otherwise the final result will be unsatisfactory. 

Another recipe : 1 lb. kid clippings ; 7 pints water ; 
1 lb. glue ; \ lb. soft soap ; 4 ozs. beeswax ; 2 pints cod 
oil ; \ lb. tallow ; 4 ozs. Venice turps ; 2 ozs. prepared 
asphaltum. Prepare and mix as above. 

In conclusion, it should be said that the manufacture 
of wax kip butts has been gone into fairly fully, as their 
manufacture represents the modern development of curry- 
ing, and illustrates better than any other leather how 
old-fashioned methods have been grafted on, as it were, 
to the use of machinery and modern methods. The trade 
is still a very large one in these goods, and as the leather 
possesses qualities which are difficult to obtain in other 
leather, whilst the supply of raw material is likely to 
continue fairly abundant, it may be safely assumed that 
not even the chrome industry will ever supplant this 
valuable section of the orthodox currier's art. 

Currying Satin or Glove Shoe Leather. — Under 
various names a variety of most useful leathers are now 

2 c 



386 LEATHER MANUFACTURE. 

finished on the grain side. Satin leather has long been in- 
cluded amongst British curried leathers, and satin calf used 
to be highly esteemed. The term " satin " is sometimes 
applied to a leather finished on the grain, the surface 
of which has not been removed or buffed, whilst " glove " 
shoe leather is usually understood to mean a leather 
which has had the grain removed : both terms are, how- 
ever, used in a somewhat arbitrary manner. It is claimed 
for the buffing process that it adds to the wear of the 
leather, as the hard natural outer surface of the dermis 
soon becomes hard, and ultimately cracks. On the other 
hand, it must not be forgotten that buffing immensely 
improves the grain of the tanned leather by obliterating 
barbed-wire scratches, frized grain, and other imper- 
fections which curriers are painfully familiar with. 

It may be mentioned here that the trade in glove hide 
has assumed enormous dimensions, mainly owing to the 
enterprise of the Americans, who, by the employment of 
machinery, and perhaps a highly protected home market, 
have been enabled to sell this leather at a very low price. 
The American tanner, by specialising on side leathers 
alone, has a decided advantage over his European com- 
petitor, who is perforce obliged to handle not only kips, 
but shoulders and bellies of different sizes and substances 
for satin purposes. However, a good trade is still done in 
grain leathers, and in the following summary it is proposed 
to give an outline of the various processes employed, 
which, although varying in different works, yet depend 
on much the same principles. 

Soaking and Splitting. — These operations are carried 
out in precisely the same way as in the case of kip butt 
dressing already described. In the case of the lighter 
classes of kip offal, shaving only is necessary, which may 
be either done by hand or machine. It might here be 
mentioned that thin kip shoulders and bellies are often 
dressed and blacked on the grain side, and are commonly 
called " black grain ; " in this case, however, the outer 
surface of the grain is not buffed away as in glove. 

As a rule, it is only the stouter and rougher classes of 



CURRYING. 387 

hide offal, or sides, which are worked up into satin or 
glove, and as the leather is full in substance, it is well 
adapted for splitting, whilst as the flesh split is also 
valuable, it is obvious the saving is great. As before 
hinted, successful splitting depends upon a proper pre- 
paration of the leather, and too much care cannot be 
taken in arriving at the proper amount of moisture it 
should contain, or in the careful treatment of the leather 
before the actual splitting commences. It is usual before 
splitting, and after damping, to thoroughly extend the 
leather by means of a suitable machine; this has the 
effect of removing coarse grain, wrinkles, &c, which 
would leave unsightly marks in the finished leather. 
This object is obtained by stoning, or "jacking," out the 
grain side of the leather on a machine of the grasshopper 
type, such as is illustrated in Fig. 77. Small curriers 
usually have a set of interchangeable tools for this piece 
of plant, and amongst them a stout brass or stone sleaker, 
which is very useful for preparing work for the splitting 
machine. 

Much might be written on proper splitting, but no 
amount of instruction will possibly make an expert 
splitter, who, by the way, is an invaluable adjunct to any 
leather works. Glove leather is now invariably split on 
the band-knife machine, and a good splitter is able to get 
his leather sufficiently uniform to avoid any subsequent 
levelling with the shaving knife, although it must be 
acknowledged that for some classes of goods this latter 
operation is an improvement. Two much care cannot be 
taken by the operative in splitting, since any damage 
clone is permanent. He should frequently examine the 
leather as it passes through the machine, and immediately 
rectify any errors in substance. The knife should also 
be kept constantly sharp, and the bevel most suitable to 
the grade of goods under treatment fully kept up. Pre- 
cautions must also be taken to guard against the flying 
emery dust from the grinding apparatus coming into con- 
tact with the leather, or a good deal of discoloration will 
be the result. As a rule, a smart boy attends the splitter, 



388 LEATHER MANUFACTURE. 

and removes the leather as it comes through, the splitter 
carefully feeding the leather on the other side. In 
America the position is reversed, the chief operative 
being the one who takes the leather from the machine. 
In America, however, several splitting machines are 
under the charge of one man, who is really responsible 
for the quality of the enormous quantity of work turned 
off by the machines. Another point about splitting 
worthy of note is the necessity for a sharp removal of the 
goods after the operation. It is a common fault to see 
leather being left about near the machine for workmen 
to walk on, or to catch the flying particles of emery from 
the wheels. The machine, too, is well worth attention in 
the way of extreme cleanliness, and it is a good rule to 
see that every part is thoroughly wiped dry and rubbed 
with an oily rag after the day's work. 

After splitting, kip leathers are first re-tanned much 
in the same fashion as described in the previous chapter. 
Hide leathers, being fully tanned, do not require this 
treatment, and are usually given a sumac bath in the 
drum. This considerably mellows the leather, and enables 
it to take a much greater quantity of grease in the sub- 
sequent stuffing processes than would otherwise be the 
case. After sumacing, the goods are scoured either by 
hand or by one of the many scouring machines. As the 
leather is to be blacked on the grain side, the removal of 
the bloom is not of great importance, so that the scouring 
may be pushed forward rapidly. After scouring, the 
leather is either taken to the sheds for hand-stuffing, or 
dried out if the process is to be done by the drum. Of 
late years the former process has almost become extinct 
in the larger establishments, owing to the cost and the 
impossibility of getting in the weight as compared with 
drum-stuffing. We will assume, then, drum-stuffing is 
the process to be followed out. It will not be necessary 
to again go into details, as they were fully described in 
the chapter on Butt-dressing, but it cannot be too often 
insisted upon that the greatest care is necessary in the 
application and selection of the various greases if best 



CURRYING. 389 

results are to be looked for. Some curriers make the 
mistake of supposing that any old grease is good enough 
for satin or glove leather ; but it is hardly necessary to 
say the results are by no means as good as when good 
fats, such as tallow or stearine, are used. The amount of 
grease put into the leather varies a good deal, but may 
be probably put at about 60 to 70 per cent., calculated on 
the dry weight of the leather. Of course the whole of the 
melted grease put into the stuffing-drum is not absorbed, 
although a good currier loses very little. The gain of 
weight in America is very much greater than in England, 
as much as 90 to 100 per cent, being obtained on the 
weight of the dry leather. This result is, however, 
largely obtained by the use of hard stearines and waxes, 
whilst the fact that the hemlock tannage is a good grease 
absorbent is probably an important factor in its favour. 
In stuffing satin leather the drum is heated up to about 
140° to 150° Fahr. before the leather is entered, whilst it 
takes about thirty or forty minutes for the melted fats to 
be absorbed by the leather. After cooling down, as 
already explained, the leather is set. In many places 
this is done wholly or partially by machine, although if 
the latter plan is favoured, the work has to be gone over 
again by hand to remove the marks remaining. The 
leather has to be in any case very fully extended both on 
the flesh and grain. If this is not well done, the grain is 
coarse, and the leather will probably be pipey and loose, 
to say nothing of the greatly increased difficulty which 
the buffer will experience in the removal of the outer 
surface. The leather is then dried in the ordinary way. 

Buffing. — Although this may be done by machine, 
yet the process is so difficult that most curriers prefer 
hand-buffing. Even the progressive American currier 
has not yet fully conquered the question of machine 
buffing, although the problem has had the serious atten- 
tion of engineers for many years past. Still, for some 
requirements a machine does the work well enough, and 
a machine of the type described in the chapter on 
Machinery (see Fig. 72) is often very useful for the 



390 LEATHER MANUFACTURE. 

purpose. A long description of the machine is not 
wanted here, but, roughly, it consists of a cylinder con- 
taining an arrangement of spiral knives fixed at the end 
of a pendulum, or vibrating arm, the whole arrangement 
being worked over a sloping table. The leather under 
treatment is laid over the sloping table, which is auto- 
matically raised to meet the action of the cutting 
cylinder by means of a foot lever. As a rule, machine- 
buffed leather has to be gone over again by hand, as the 
machine is apt to miss the thinner parts of the hide. 

In hand-buffing the whitening sleaker is used, and 
only expert workmen are trusted with the operation. 
The grain is first damped with a soap solution, and the 
buffer takes off very thin shavings from the surface. 
Great care should be taken to avoid scratches, stabs, or 
" run " marks ; otherwise the finished leather will be 
unsightly and of lower value than would be the case with 
good work. 

Blacking and Setting. — After the buffing operation, 
leather for glove or satin is then blacked. Different 
curriers have different methods ; some mordant the grain 
with a logwood solution, and apply the striking iron 
liquor at once. The leather is then well set out on flesh 
and grain, and after the latter had been dried, a solution 
of some filling material is applied with a soft sponge. 
For hide sides the following methods may be taken as 
fairly representative, whilst it also obviates to some 
extent the tendency toward pipey grain before alluded to. 
Brush over the grain with a weak solution of logwood 
liquor (about \ lb. to the gallon) to which has been added 
a little ammonia. Then well set out the leather on the 
table, which has previously been rubbed over with tallow 
to make it stick. Care should be taken to give the side 
a good pattern, and this is only to be obtained by the 
workmen using the setting sleakers by following the 
natural lay of the hide. After this setting, the leather 
is again washed over with the logwood liquor, when a 
coat of some suitable ink or iron liquor is given. The 
sides are laid by in a pile, and are then thoroughly 



CURRYING. 391 

canked on the flesh side, the grain being this time stuck 
to the table by the use of oil. After this the sides are 
again set on the grain side to the table, a coat of dubbin 
being first brushed on to the latter. After a further 
sleaking, to remove surplus particles, followed by a 
glassing or pebbling, a coat of paste or bottom size is 
applied with a sponge or brush. Various mixtures are 
used, but the following will give excellent results, viz. a 
quarter-pound each of best glue, oil, and flour, mixed 
in about two quarts of hot logwood liquor. This is 
a representative formula, but different tannages require 
varied" pastes and sizes, and often want a good deal of 
modification to suit individual requirements. 

Finishing Satin or Glove Leather. — After drying out, 
the leather is now whitened ; in some places this opera- 
tion is done by machines, as they are quicker in their 
action than hand labour. The same class of appliance as 
that spoken of for buffing does whitening fairly well, 
although opinions as to its merits vary considerably. If 
the leather is to be whitened by hand, a slight skiving 
over with the sleaker is sufficient, as in this case it is only 
necessary to clean the flesh side for appearance' sake. 
When the leather is whitened it is then trimmed at the 
edges, and lightly bruised with the arm-board to soften 
it. This operation is, of course, done from the grain side 
so as to avoid raising the grain ; it requires care and 
judgment, and very little pressure should be given to the 
coarse and loose part of the hide. Satin is then again 
sleaked down on the grain side with a dull sleaker to 
remove the bruising marks, and glassed or pebbled as 
preferred. The leather is then given a coat of finish in a 
warm room and dried out very thoroughly. Some people 
who prefer a dull finish use either a flour or gum solution, 
a few drops of ammonia being added to it if any difficulty 
is experienced in its application. A good finish may be 
prepared as follows : In 4 quarts of logwood liquor dis- 
solve 1^ lbs. of glue, 4 ozs. of brown soap, 3 pints of cod 
oil, and 2 \ ozs. of beeswax. This is applied with a suitable 
pad covered with cotton wool, over which is tacked a 



392 LEATHER MANUFACTURE. 

piece of buffed leather. Extreme care must be taken to 
avoid marks of any kind in the application of the finish, 
as it is impossible to remove them later. The leather 
after thoroughly drying is now again glassed, oiled with 
warm cod oil, again hung up until the oil has penetrated, 
when it is ready for the finished-leather store-room. 

Satin or glove leathers, it is true, do not now enjoy the 
popularity they did before the introduction of the chrome 
tannage. Still, the trade is yet a good one ; and as the 
leather is extremely useful for such work as the cheaper 
grades of women's and children's footwear, it is very 
unlikely it will ever become obsolete, and there is no 
reason, if the above directions are carefully followed out, 
why the reader may not get good results on this class of 
leather, even if he has not been accustomed to this special 
work. 

Levant Leather. — Until the advent of chrome leather 
the levant trade was a most important branch of the 
leather-dressing industry, and even now kip curriers still 
find it a useful addition to their business. The term 
"levant" is usually applied to an embossed or printed 
leather, finished on the grain side with a bright surface, 
and dressed with oil only, i.e. not stuffed with fats and 
greases as in the case of waxed leathers. This section 
of leather manufacture provides a very useful outlet for 
poor goods unsuitable for wax and satin, and very little 
hand labour is required under modern conditions. 

Soaking and Splitting. — Taking East India kips as 
an example, the process is as follows : They are first 
carefully soaked until the water just oozes out on sharply 
pressing, and after lying in pile for a few hours they 
are softened by a short drumming, and are cut straight 
down the centre of the back. 

They are then split evenly on the band-knife machine, 
and are either first scoured or taken away for retanning. 
This is invariably done in the drum, a mixture of 
sumac, myrobalan, or gambier liquor being used, often 
strengthened with a certain proportion of good oakwood 
extract, This retanning is an important part of the 



CURRYING. 393 

levant business, as India kips are very often undertanned, 
and if this is not reckoned with, the finished leather will 
be hard, and will refuse to take the necessary quantity 
of oil to make it profitable. 

Setting, Buffing, and Embossing, — After drumming 
for about eight hours, either drain up the goods thoroughly, 
press or squeeze by machine, or strike them out on the 
flesh side. Then take them to the drying sheds and 
lightly oil with linseed oil on the grain side and hang 
up to samm. They are then well set by means of a 
sharp sleaker on the flesh side, and hung up and dried 
out, a'little oil being used to stick the kips to the 
table. 

"When fully dry go carefully over the grain side, and 
carefully buff all broken grain, first slightly damping 
the surface with a sponge and sleaking the place to be 
buffed well first with a dull sleaker. After buffing 
where necessary, sort the kips for printing, throwing 
all those inclined to be "pipey" or coarse-grained out 
for the heavier style of print, such as seal or big-star 
grain. 

The embossing or printing is now usually done by 
means of a suitable engraved roller (see Figs. 81, 82), the 
entire side being subjected to a fair pressure in passing 
through the rollers. A better impression is obtained 
if the leather is first damped slightly. The kips are 
then dried out, and may be stored in this condition until 
ready for finishing. 

Blacking. — The goods are now dried out after all the 
pleats made by the machine are carefully trimmed out, 
or remedied as far as possible by going over them with 
a small hand roller, the design being of course similar 
to the large one used in the first place. After embossing, 
the nest process is the blacking operation. This is done 
by giving the grain side a coat of logwood decoction, 
and subsequently another coat of levant ink, care being 
taken to keep the flesh side as clean as possible. When 
trimmed the kips should be well softened and grained. 
This is now almost always done by the boarding machine, 



394 LEATHER MANUFACTURE. 

the bulk of the work being done to the flesh side to 
prevent piping (Fig. 71). 

Seasoning and Glazing. — After this softening the 
goods are seasoned, care being taken to have the season- 
ing material well brushed into the grain. A suitable 
seasoning is composed as follows : 6 pints of bullock's 
blood ; 4 pints of logwood solution ; 2 pints of blue archil 
solution, and \ pint of spirit of wine. When the season 
has well dried into the leather, have the kips again well 
grained, taking special care that the design is made as 
perfect as possible and that " piping " is avoided. 

A second seasoning is then applied composed of the 
following ingredients : 7 pints of blood ; 4 pints of 
logwood ; 2 pints of new milk; 1 pint of archil liquor; 
\ pint of spirit of wine ; and 2 ozs. of burnt sugar. 

After the goods have been well dried they are usually 
fluffed on an emery wheel to clean the flesh, and are 
then ready for glazing. It is best before taking them 
to the machine to slightly wipe them over with a rag 
dipped in linseed oil, as it helps to prevent dragging 
or scratching under the pressure of the glazing-glass 
or agate. The machines in use are many, but those of 
the type shown in Figs. 77 and 78 are representative. 
After glazing, the goods are again carefully grained, 
the pattern being carefully preserved. This requires a 
good operator, as it is impossible to rectify mistakes 
made in this final graining. 

Oiling. — A final oiling now completes the process. 
This is applied with a suitable wad or flannel rag, the 
oil being warmed and spread evenly over the surface 
of the grain. Linseed or mineral oil is used for the 
purpose, according to the quality of the goods. Some- 
times a mixture of both is given, whilst others oil off 
solely with the cheap mineral product. 

Care should be shown in the oiling, otherwise, if too 
much is given, it will penetrate to the flesh side, and 
spoil the appearance of the finished leather. The kip 
sides are now sorted into qualities and substances, and 
are ready for the shoe manufacturer. 



CURRYING. 395 

Currying Various Leathers. Wax Calf Skins. — From 
an interesting series of articles upon currying which, 
appeared some years ago in a technical journal, now 
extinct, we make the following extracts, as they illus- 
trate the difference between the new methods described 
in this chapter, and the old ideas on which they are 
based : — 

" Calf skins of various weights (tanned), from 1\ lbs. to 8 
or 9 lbs. each, are curried for shoe purposes. Light skins 
should not be shaved so much as heavy ones ; the flesh 
should merely be taken off and the veins taken out, so 
that they may be level in the butt part, being first of all 
shaved over ; they do not require flattening except they 
are lumpy — that is, thicker in one part than another. 
After they are shaved, scour, flesh, and grain, give them a 
good sumacing, and let them lie for a day or two. Warm 
the liquor before they are sleeked out of that ; stiffen them 
a little in the shed. If they are not very coarse in the 
grain they need not be set on the grain at all, as it will 
be found that it renders them much softer and more after 
the style of French skins. Before stuffing, put a little oil 
or dubbin on the grain, turn over, and sleek them on the 
flesh, then put the dubbin on the flesh and hang on two 
loops in the shed to dry. When dry, take down and put 
a little dubbin on the grain, commonly called ' tallowing,' 
and lay them aside for a few days. Heavy skins require 
more shaving than light ones, and therefore take more 
dubbin. After they have lain by, if heavy skins, slightly 
raise the grain with a toothboard or cork. Sleek the 
grease off the flesh and grain, and whiten them with a 
turned sleeker or knife, whichever the dresser uses best. 
Bruise on the flesh and grain up, then wax them. The 
process of waxing is to colour on the flesh — that is, to put 
black on the flesh (lampblack and oil). Now glass down 
on the flesh, and size on the same side ; hang up for the 
size to get quite dry, then glass on the same side. 

Calf Skins for Memel weigh from 30 to 40 lbs. per 
dozen. These are shaved level, scoured flesh, and grain, 
care being taken not to injure or break the grain ; they do 



396 LEATHER MANUFACTURE. 

not require much sumacing, if well tanned. Sleek out on 
the grain and hang in the shed to samm ; when stiff 
enough, set them on the grain, and print them with a 
memel or straight-grain roller. Oil on the grain, turn 
over, and lay flat on the table ; but do not set them on it. 
Stuff them on the flesh ; but they do not require so much 
stuffing or dubbin as wax leather ; now hang up to dry. 
Some persons have them printed after they are blacked, 
others will not have them printed at all when dry. Next 
take them down and black on the grain side, and size ; 
when well hardened, slightly grain up, and put them 
in the stove or drying-room ; when dry, clean the flesh 
side, and finish graining, then oil with linseed oil, when 
they are ready to cut up. 

High Shoes, Black Grain. — These are mostly cut from 
the best part of the hide, free from cuts on the grain side, 
and must not be shaved so low at the bottom part. Scour 
flesh and grain, compo if desired, as it renders them soft 
and pliable, and they take more stuff; now hang in the 
shed to samm ; set on the grain, if required, oil, and print 
before stuffing, with a straight or cross-grained roller. 
Turn over and stuff on the flesh side ; they will generally 
take twice as much stuff as wax legs, in fact you cannot 
give them too much. Now hang in the shed to dry, and 
when dry, black on the grain and oil. When the oil is 
absorbed, raise the print with a cork or toothboard, then 
hang up in the drying-shed ; before doing so, however, 
they should have a coat of dubbin on the grain, if they 
have lain by for some time. Sleek the grease off the 
flesh, bruise the flesh, grain up and give them a good coat 
of clear oil on the same side : they are then fit for use. 

Split Cow-Hides for Brown Bags. — These are shaved 
lightly on the flesh side until they are level ; they are 
then scoured, flesh and grain, and sumached ; next sleeked 
out of the sumac ; then put into the shed to samm, and 
when stiff enough are printed on the grain. Stiff tallow 
dubbin is laid over the grain, buck or deer tallow being 
preferred. Stuff on the flesh if desired, otherwise slightly 
glass down on the flesh, and hang up to dry. After 



CURRYING. 



397 



drying, raise the print, and bruise on the flesh. See that 
this side is free from grease, then glass the same side, and 
brush the grain with a good hair-brush, when they are 
ready for sale." 

Blocking Boot-fronts. — This operation, which was for- 
merly conducted by the bootmaker, sometimes forms a 





Fisr. 59. 



branch of the currier's business. For the following 
description of the blocking-machine, and the method of 




Fig. 60. 

working it, we are indebted to Ure's " Dictionary of Arts, 
Manufactures," &c. The leather, being dressed as before 
described, is cut out as at a, Fig. 59, and when folded or 
doubled, appears as at b. 

In Fig. 60, 1 1 1 is a strong frame of woodwork ; 2 



398 LEATHER MANUFACTURE. 

represents a pair of cheeks, strongly fastened in the 
frame, and regulated to a distance by a screw. These 
cheeks are lined with zinc. 3 is a strong plate of metal, 
the angle at 3 corresponding exactly with the angle of 
the cheeks ; the ends of this plate are fixed in movable 
plates passing down the columns 1 1 ; 4 is a handle by 
which the instrument is worked, and which, by cog- 
wheels acting on the movable plate, brings 3 down- 
wards. The front a is laid, after a thorough soaking in 
water, over the cheeks 2 ; the handle being turned, 3 
comes down upon the front, and forces it through the 
small opening between the cheeks, and when brought out 
below the cheeks it has the appearance given at c. 
The plate 3, having carried the front between the cheeks, 





Fig. 61. Fig. 62. 

is removed (below), and the weight 5 assists in bring- 
ing the perpendicular movable plates to their place, 
when 3 is again put in position, and thus the operation 
is rapidly carried on. After this the fronts are regularly 
placed on a block, being forced into position by an instru- 
ment called a flounder (Fig. 61), and tacked to their 
place. After this they are slightly oiled and dried. Some 
ingenious methods have been adopted for softening fronts 
so as not to disturb the Hocking. They are whitened on 
a very sloping beam or horse (Fig. 62), which enables 
the workman to hold them better than he could on the 
common beam. They are again blocked by the waxer, 
and when these processes are carefully performed much 
trouble is saved to the bootmaker. 



CHAPTER XXXI. 

MACHINERY EMPLOYED IN LEATHER 
MANUFACTURE. 

" Stocking " or Softening Machines. — Depilation and Fleshing Plant. — 
Machines for Crushing and Grinding Tanning Materials. — Solo 
Leather Finishing Machinery. — Leather Dressing Machinery. — 
Scouring and Setting Machinery. — Embossing and Softening 
Machinery. — Tanning and Stuffing Drums. — " Boarding " and Soften- 
ing Machines. — Machinery used in Chrome Leather Manufacture. — 
Machinery used in the Beam House. — Finishing Machinery for 
Chrome Work. 

Duking the past few years the use of mechanical aids has 
greatly increased in every department of the leather 
trade. True, the British tanner is not so enthusiastic 
over their adoption as his hustling American rival, as he 
has to deal with smaller quantities and more varied lines 
of goods ; in a word, he has not the opportunity of speciali- 
sation common to the United States. On the other hand, 
it must be admitted that many of the best machines had 
their origin on the other side of the Atlantic, and that 
they have only been adopted in other parts after the 
progressive American had, by long and costly experiment, 
proved their utility. The inventiveness of the native 
American, and the readiness of tanners to take up new 
ideas, have been important factors ; in short, a variety of 
causes have favoured the transatlantic machinist, the 
cost of skilled labour being, perhaps, amongst the most 
important. 

Of late years, however, a good deal of tanners' machinery 
has been made in England and the Continent, and there 
is now very little to choose in quality or price between 



400 LEATHER MANUFACTURE. 

the various makes, although the Americans admittedly 
do not put so great an amount of finish into their work. 
Naturally, the greatest chance for the leather trades' 
engineer has been in the direction of the lighter leathers, 
and there is no doubt but that the introduction and 
exploitation of chrome leathers has proved his great 
opportunity. 

The cost of machines suitable for sole leather tanners 
and their enormous capacity have made it somewhat 
difficult to successfully push this class of plant. Until 
quite within recent times many of the sole tanneries 
have been on a very small scale ; modern competition is, 
however, gradually proving too strong for them, and the 
industry is drifting into larger hands. Stronger tanning 
materials have also taken the place of the British oak- 
bark, and to-day there are many large tanneries in the 
Warrington and Liverpool districts with a capacity of 
one to three thousand hides per week. Such yards as 
these can, of course, profitably employ machinery, and 
the persistence of the leather trades' engineer is thus 
slowly, but surely, having its reward. It will be im- 
possible, in the space at our disposal, to explain or 
enumerate all the various machines now employed in 
light and heavy leather manufacture, but enough will 
be said to enable the reader to become au courant with 
the most important developments introduced within the 
past few years. 



Machinery used in Sole Leather Tanning. 

" Stocking " or Softening Machines. — The old- 
fashioned plan for softening the soaked hide was to 
" break " it over on the half-round tanner's beam with a 
blunt knife. This plan is still followed out in small 
yards, and in countries where labour is cheap and 
plentiful. This method is now supplemented or super- 
seded by the use of the " stocks." This machine consists 
of a metallic box, in which rise and fall two heavy 



MACHINERY IN LEATHER MANUFACTURE. 40I 

kaniniers, raised alternately by projections in a revolving 
wheel. The action is very effective, being a sort of 
kneading or pounding, and the most obstinate hides give 
way to the treatment. The duration of stocking varies 
from ten minutes to half an hour. The ordinary form 
of stocks in use for softening Indian kips, China, " flint," 
and other stubborn hides is shown in Fig. 6, p. 111. 
A more modern device, which claims some advantages, 




Fig. 63. 

is the American double-shover, the principle of which 
is shown in Fig. 63. 

There are other forms of stocks upon the market, but 
the above two examples give a fairly accurate impression 
of the main principle involved. 

On the Continent of Europe a machine of a somewhat 
different type is used, which possesses the advantage of 
being lighter in its action upon the thinner parts of the 
hide. The idea is simple, being that of a pair of rollers 
pressed together by a spring. One roller is studded with 
blunt pegs, which corresponds to grooves in the other, 

2d 



402 LEATHER MANUFACTURE. 

and so arranged that the hide is subjected to a very 
thorough kneading. 

The method of stocking and softening varies very 
much in nearly all yards, but in spite of the march of 
engineering improvements, the stocks remain much the 
same in principle as in the day when the tanner probably 
borrowed the idea from his cloth-making confrere. For 
the lighter kind of skins, drum tumblers are effective 
for softening ; but it will be more convenient to deal 
with light leather machinery under a distinct heading. 

©epilation and Fleshing Plant. — After the preliminary 
softening and cleaning, the hides intended for sole leather 
are then ready for some process which will swell the pelt 
and loosen the hair so that it can be easily removed. 
The most common method is to immerse the pelt in a 
lime solution, which not only loosens the hair and swells 
the hide, but converts the fat it contains into a lime soap, 
at the same time so loosening the cutaneous tissue that 
the surplus flesh is easily worked off. Other methods of 
unhairing depend upon the use of sulphides, and putre- 
faction, technically termed "sweating." By whatever 
means, however, the hair is loosened, it is usually re- 
moved by hand, as the labour involved is not costly; 
and so far attempts to do the work by machine — at any 
rate on the heavier hides — have not been particularly 
successful, owing mainly to the fact that it is generally 
necessary to supplement the machine work by hand 
labour, as it is often difficult to remove short hair, or 
that from patches where the pelt has been insufficiently 
softened. Much, however, depends upon the require- 
ments of the market and the output of the yard. The 
principle of many of the various unhairing machines 
consists of a rapidly involving cylinder, fitted with 
spiral blunt knives, working over another rubber-covered 
cylinder, the hide being fed or introduced between the 
two. The Turner Tanning Machinery Co., Peabody, 
U.S.A., and Leicester, Eng., have a machine upon the 
market large enough for sides and whole hides, which 
is shown in Fig. 64. It is claimed by the inventors 



4»4 LEATHER MANUFACTURE. 

of this machine that many hundreds of them are in 
operation in the largest tanneries in all parts of the 
world for unhairing, fleshing, and general work in the 
beam house. The cost of big machinery is naturally 
great, and the expenses of running fairly so ; it is there- 
fore obvious that an appliance of this kind is only 
profitable in large tanneries. 

Much the same criticism might apply to the operation 
of fleshing, which invariably follows unhairing. It is 
questionable whether any machine has yet been invented 
which will give cheaper or better results on hides than the 
old plan of paring off the loose flesh by the use of a sharp 
knife on the half-round beam. Machinery, it is true, does 
the work rapidly, but a certain amount of damage is in- 
evitable, whilst it is difficult to do the work uniformly. 
In the case of calf, goat, and sheep skins, fleshing 
machines are used with great success ; in fact, hand flesh- 
ing has been displaced almost entirely in the large chrome 
tanneries, as machine work is cheaper and more regular 
in output. It must be remembered, however, that all sole 
leather is invariably sold by weight, so that the intelli- 
gence of the skilled workman is very useful, as much un- 
necessary tissue may easily be cut away by machine, with 
the result that the slight saving in labour may be 
swamped in the deficient weight of the finished leather. 

It is, however, only fair to add that there are several 
large sole leather yards turning out a good mixed tan- 
nage of sole leather which now use the fleshing machine 
very successfully, so that it is probable it is only a 
question of time when the old beamsman will become a 
thing of the past. Improvements are being continually 
introduced, and the prejudice against the use of machinery 
passing away, whilst the unceasing competition of the times 
naturally favours the application of any piece of plant 
likely to cheapen a process which is of a very costly nature. 
Machines for Crushing and Grinding Tanning Mate- 
rials. — As this chapter does not profess to deal with the 
technique of tanning, only as far as is necessary in 
explaining the use of machinery, no attempt will be 



MACHINERY IN LEATHER MANUFACTURE. 405 

made to describe the tannins in detail. Most of them, 
however, require some preparation by machinery in the 
way of breaking or grinding by means of bark mills or 
disintegrators. The object is to grind the material so 
that the liquor has ready access to the interior cellular 
tissue, in which most of the tannin is found. The bark 
mill in general use consists of a toothed cone working 
inside another similarly constructed cone, arranged much 
on the same principle as a coffee mill. A preparatory 
breaking by a special machine is also necessary where the 
bark to be ground is in long strips, and this is usually 
done by means of toothed breakers. A common form of 
mill is constructed by the well-known Exeter firm of 
Huxham and Browns, and B. and D. Wright, Leeds. An 
improved bark cutter is made by the Turner Machine 
Co., Peabody, United States, and is durable, simple, 
and effective ; and it is claimed by the inventors that it 
will prepare forty cords of bark per day for the leaches. 

Such materials as valonia and myrobalans are usually 
broken by means of the machines known as disintegrators, 
such as are used to pulverize bones, &c. The principle 
is simple, and depends upon knocking the material to 
powder by the action of rapidly revolving beaters, which 
in some cases are driven at a speed of between 2,000 and 
3,000 revolutions a minute. This class of machinery is 
very effective, but the consumption of power is rather 
great, whilst the fine dust is apt to prove troublesome. 
For some purposes myrobalans are only required roughly 
crushed by the tanner. In this case a machine with, 
fluted or toothed rollers is more useful than a disinte- 
grator, as less power is required and the proportions of 
dust is very little. Yalonia — a species of large acorn cup 
from Southern Europe — may also be satisfactorily crushed 
by this class of machinery. The most common form of 
disintegrator is shown in Fig. 65. 

Many other varieties of devices for preparing tanning 
materials are also in vogue, but the examples mentioned 
fairly represent the general principle on which most of 
them are constructed. In England machinery is not 



406 



LEATHER MANUFACTURE. 



much favoured for carrying tanning material to the 
leaches or extraction pits, but in America "conveyors" 
of various kinds are freely used. These consist often 
of endless iron chains carrying wooden cross-bars at 
intervals, working along suitably constructed spouts. 
As the use of conveyors is only profitable in large 
tanneries where labour is dear, and, furthermore, their 




Fig-. 65. 



design has already been explained on p. 161, it would 
serve no useful purpose to here further enlarge upon 
them. 

Sole Leather Finishing Machinery. — Sole butts after 
tanning are usually drained of surplus Hquor, and then 
are given a coat of oil on the grain side and allowed to 
partially dry, and are then " struck " or " pinned " out. 
The object is to stretch and render the grain even, and 
often to scour out as much bloom — a whitish deposit left 
in by tanning — as may be desirable to suit the require- 
ments of the market. Many tanners of best quality oak- 
bark leather still persist in doing this by hand, using a 



MACHINERY IN LEATHER MANUFACTURE. 407 

triangular tool called a pin, and thoroughly extending 
the leather over a horizontal beam or " horse." 

Of late years, however, machinery has been successfully 
introduced for the purpose, and nearly all the biggest 
English yards employ various types of machines for 
striking. The most popular form of machine for striking 
offal is that invented by Priestman some years ago, 
the principle of which remains the same, although im- 
provements have been added from time to time. A 
common form of this appliance is shown in Fig. 20, 
p. 165. 

The "principle is simple, and consists of a revolving 
cylinder, to which are attached V-shaped blunt brass 
knives, under which the leather is fed. The pressure is 
regulated by a foot-lever acting on a movable bed. The 
amount of work turned off by this machine is very great, 
but it is not very well adapted for irregular-shaped pieces 
of leather, such as bellies, &c. 

Many tanners now use the striking machine for butts 
invented by Wilson (Fig. 66), which is perhaps as near an 
approach to hand labour as can be obtained. The leather 
is carried over a revolving drum, and the grain is operated 
upon by blunt knives working outwards from the centre. 
Where it is necessary to remove the bloom, slabs of stock 
stone are substituted for the knives. This piece of plant 
has been running for many years in some yards and has 
proved a valuable help, as the cost of striking is nothing 
like so great as hand labour. It is, however, more es- 
pecially useful to large tanners, as the first cost is fairly 
high, and it requires a firm foundation, the oscillating 
motion being rather pronounced. A modification of this 
type of machine is also now freely used for pinning offal. 

Sole leather, after lightly oiling and drying, is then 
submitted to a rolling operation to give it the necessary 
solidity and firmness. On the Continent a different 
method prevails, and the leather is well hammered by a 
machine known as the Marteau-a-battre, the action being 
much the same as that of the well-known steam 
hammer. 



MACHINERY IN LEATHER MANUFACTURE. 409 

The old type of rolling machine consisted simply of a 
loaded box, to which was attached a brass roller. This 
was dragged over the butts, which were spread out upon 
a plank or zinc bed, and, although slow and cumbrous, 
the method is still regarded as the perfection of leather 
rolling. Fig. 22, p. 166, shows a form of spring butt 
roller by Huxham and Browns in which the necessary 
pressure is obtained from springs placed above the roller, 
which runs alternately backward and forward over a flat 
table beneath a fixed girder. The pendulum roller, 
Fig. 23, p. 167, is especially suited for sides, such as East 
India kips or Singapore leather, in which great firmness 
and a high gloss is necessary. The roller being narrow 
lends itself readily to the inequalities of substance, and its 
construction is very convenient to the manipulation of 
the irregular belly and shank portion of the side under 
treatment. Its oscillating motion causes much vibration 
and noise, so that it is best fixed wherever possible on 
the ground floor. It is, however, cheap, easy to make 
and repair, and well adapted to special classes of work such 
as are mentioned above. 

A familiar and useful type of machine is the " C " 
roller, in which the leather is passed between two brass 
covered rollers. Practically any pressure may be 
obtained by a weighted lever attached to the top roller, 
but experience has shown that this type is unsuitable to 
butts, as it destroys the flat appearance, or — to use a 
technical expression — makes them " baggy." For bellies, 
shoulders, and splits this variety of machine is very 
suitable, as the cost of manipulation is not great by 
reason of the quantity of work done, whilst a simple 
reversible motion, obtained by using a crossed and open 
belt, obviates, to a large extent, any jumping of the 
rollers when narrow pieces of leather are under treatment. 
It may be added that nearly in all cases leather is rolled 
twice, the two operations being designated " rolling on " 
and " rolling off." After complete drying, sole leather 
is ready for the market,, although in some cases colouring 
composition are applied to the grain side, and a final 



4 io LEATHER MANUFACTURE. 

brushing — which is now often done with a machine — 
given to bring up an attractive-looking gloss. 

Leather Dressing Machinery. — The mechanical ap- 
pliances employed under this heading are extremely 
numerous and ingenious, and, since the introduction of 
the chrome tannage, have been greatly augmented, 
although it must not be assumed that some of the 
machines mentioned here are not both used on chrome 
and other forms of leather making. 

The term " dressing leather " is fairly comprehensive, 
and embraces harness, saddlery, mechanical, accoutre- 
ment, boot and bookbinding leathers, &c. Each of these 
branches of the leather industry is often a special business, 
but there are certain types of machines fairly common to 
all. 

As most tanned leather is rough and uneven when it 
leaves the hands of the tanner for the currier, it is there- 
fore necessary to equalize the substance in some measure. 
For harness and belting leather it is only usual to remove 
the loose flesh and the marked inequalities of the butt, 
but for such purposes as shoe leather, which depend upon 
a flesh side finish, this preliminary operation is very com- 
plete, and is technically known as shaving, an operation 
requiring a long training and a high pitch of perfection. 
Within recent years this process, which is done by 
laboriously paring the hide or skin with a suitable knife 
over an inclined " beam " or block of lignum vitce 
(Fig. 58, p. 371), has been successfully attempted by 
machine (Fig. 67) ; in fact, by far the greater part of 
chrome tanned leather is now shaved in this way. 
Chrome leather, mainly on account of the looseness of 
its texture, is difficult to shave by hand, whilst the 
cost on goat skins makes it almost prohibitive. The 
principle of the shaving machine depends upon passing 
the damp leather under a rapidly revolving cylinder, 
to which is attached a series of steel knives, kept auto- 
matically sharpened by emery wheels. The leather 
is pushed up to the knives by a foot-lever actuating a 
rubber roller, and by a screw arrangement the distance 



MACHINERY IN LEATHER MANUFACTURE. 



411 



between the cutting and cushion cylinders may be 
regulated to suit the requirements of the operator. This 
piece of currier's plant is one of the most ingenious yet 
introduced, and is fast superseding hand labour on the 
lightest classes of goods. It is, however, yet capable of 
improvement, as it is rather dangerous to the operator, 
and somewhat deficient in reducing power on a close, 
firm texture, whilst the flying emery and steel dust is apt 
to stain ordinary vegetable tanned leather. 




In practice both untanned and tanned hides are often 
divided into two or more portions by machine. The 
principle employed in splitting " green " hides and skins 
consists in passing the swollen and limey pelt over a 
wooden drum, whilst the division is made by the action 
of a rapidly vibrating knife. Attempts have been made 
to do green splitting by means of the band-knife machine 
(see Tig. 68), with a fair measure of success, and there 
seems no real reason why the difficulties should not be 
conquered with a little determined ingenuity 



412 



LEATHER MANUFACTURE. 



Tanned leather is now almost universally split on the 
band-knife machine before mentioned. As the name 
implies, the cutting is done by means of an endless steel 
belt, which travels over two large pulleys, the edge being 
kept sharp by the automatic grinding of emery wheels 
below the machine. The machine is rather complicated 
and fairly expensive, but remarkably useful. The damp 
leather is fed between brass rollers to the knife's edge, 
the inequalities being provided for in the under roller by 




Fig. 68. 



small eccentric brass sections, which in turn press upon a 
resilient rubber cylinder. This machine is capable of 
getting through an enormous quantity of work, but 
requires the services of a skilled and intelligent operator 
to secure good results. Butts for army upper and 
kindred purposes are split on an older form of machine 
known as the " Union " (Fig. 54, p. 322), the leather 
being pressed down and drawn over a fixed knife. For 
work of this class this machine has some advantages, as 
the split leather is more even in substance. 



MACHINERY IN LEATHER MANUFACTURE. 413 

Scouring and Setting Machinery. — During the pro- 
cess of tanning by immersion in bark liquors, &c, the 
grain side of the leather, as already stated, becomes more 
or less filled with a whitish deposit called " bloom," 
known to chemists as ellagic acid. In most cases it is 
necessary to remove this, as it interferes with subsequent 
operations. The principle of the scouring machines is 
much the same as that followed out in sole-leather 
"pinning," where, indeed, the object aimed at is almost 
identical. As a matter of fact, it is usually only the 
heavier classes of upper belting and harness leather 




Fig. G9. 

which are scoured by mechanical aid, and for this purpose 
a machine of the type illustrated in Fig. 69 is used to some 
extent in England. The leather is spread in a wet con- 
dition on a movable table, and is subjected to the action 
of a reciprocating head, which has a most ingenious 
motion. The amount of work these appliances get 
through is very great ; but the first cost is heavy, and, 
in consequence, they have to be fairly fully employed to 
be profitable. 

An older type of machine, known as the "Bourdon 
Scourer," is shown at Fig. 17, p. 156. In this case the 



414 LEATHER MANUFACTURE. 

wet leather is passed under a cylinder into which are 
fixed projecting slabs of stone, which revolve at a high 
rate of speed, the leather of course being pressed up to 
the revolving working part by means of foot-levers 
actuating a suitable cushion. This machine is suitable 
for heavy leathers for military purposes, &c, but is little 
used for the finer classes of manufacture. 

Leather is, after drum-stuffing, extended or " set " to 
eliminate the stretch and to give it pattern, and then 
dried. The same operation is necessary for chrome 
tanned leather after milling in fat-liquor, which is 
simply a weak emulsion of soap and oil modified to 
suit the particular method of leather manufacture. As 
the labour involved in setting is rather excessive, but 
purely mechanical, machinery has been introduced with 
great success in recent years. For belting leather the 
type shown at Fig. 69 is also used for this purpose, but 
there is no standard machine used by upper-leather 
manufacturers for setting, although many machines are 
capable of doing good work at a low cost where the shape 
of the leather is fairly regular. 

Embossing and Softening Machines. — Certain leathers 
for shoe, upholstery, bag, and fancy purposes are often 
printed or embossed to imitate the natural marking of 
some other skin ; thus sheep skin or basil is frequently 
stamped with a design to imitate morocco or alligator 
hide, whilst cow-hide, and even the flesh split, is 
embossed and finished to imitate the well-known marking 
of pigskin for legging purposes. Levant and memel 
leather for common and heavy boots are embossed with 
popular patterns, termed "star," "pebble," &c, and 
thousands of Bombay -tanned kips are stamped with 
a long barley-shaped grain and sold as cow-hide. All 
the smaller skins are embossed by passing them in a 
damp condition beneath an engraved roller. The more 
simple designs are cut by hand on iron or copper rolls, 
the more elaborate being electrotyped, whilst floral and 
artistic designs are impressed by submitting the leather 
to pressure under a prepared plate. The ordinary form 



MACHINERY IN LEATHER MANUFACTURE. 415 

of embossing machine is shown at Fig. 81, p. 432. The 
embossing roller is now made in the shape of a hollow 
cylinder, and is thus easily removed from the working 
spindle. The most common size in use is the 4 ft. 6 in. 
machine, which takes the kip side or sheep skin quite 
easily. The smaller machines with 5-in. or 6-in. rollers 
are now seldom used, as the larger machine turns out 
the work faster and better. 

Tanning and Stuffing Drums or Tumblers. — As drum- 
tumblers are used by the tanner and light' leather manu- 
facturer very freely, it will be perhaps necessary to say 
a few werds on them here, although these machines have 
been to some extent dealt with in the chapter on Kip- 
Leather Currying. The form of tumbler illustrated in 
Fig. 70, p. 416, gives a fair idea of its construction and 
form ; but it will be seen from the design which appears 
here that the drum is capable of many modifications. 
Some users prefer the door in the side as shown in Fig. 
70, whilst others insist upon having the opening in 
the centre. The latter style has the advantage that 
the drum may be swung upon an axle, and this is a 
decided help when power and vibration are considerations. 
Some makes of tumblers are fitted with pegs standing 
up in the interior ; others, again, possess shelves. A 
good deal depends upon the class of work required, or 
the individual fancy; but as the experience of expert 
engineers is always available, it is not necessary to take 
up valuable space by going very fully into these points. 
It is important, however, to note that a tanner's tumbler 
should be strongly built of the best seasoned timber, and 
that all exposed iron work is covered with some material 
which does not corrode by the action of the tannic acid ; 
otherwise stained and spoilt leather is a certain result. 
These drums are also used for tanning proper, bateing, 
washing, &c, by the upper leather tanner, whilst the 
manufacturer of the lighter leathers finds them indis- 
pensable for re-tanning, sumacing, dyeing, stuffing, 
and a host of other purposes which will readily occur 
to the reader. In chrome tanning, too, the drum is 



4i6 



LEATHER MANUFACTURE. 



wanted in many ways, so that simple though this piece 
of tanning plant may be, yet it is important enough 
to warrant the attention of the leather trades' engineer, 
who has succeeded in improving it in many ways during 
the past few years. The improved form of stuffing-drum 
shown in Fig. 70 is fitted with an apparatus for intro- 
ducing the melted greases and hot air. 




Fig. 70. 

"Boarding" and Softening Machines. — Many forms 
of leather have to be softened by mechanical means, and 
various methods are employed to do this, according to the 
characteristics required. The old-fashioned tool, which 
is still used to a large extent, consisted of a suitably 
covered pommel, which was attached to the hand or arm 
under which the leather was rubbed. This has the dual 
effect of softening the leather and bringing up the 



MACHINERY IN LEATHER MANUFACTURE. 417 

familiar pattern of the marking of the grain. The 
softening of levant shoe leathers is now done extensively 
by machinery, and for the rougher part of the work it 
has completely displaced the hand process. A common 
type of softening machine is shown at Fig. 71. In 
mineral tannages, such as alum and salt, or chrome, the 
softening or stretching of the fibre is an expensive 
business, and special machines, described in the section 
dealing with Chrome Leather Machinery, are freely used. 
The final operation necessary to the finishing of most 
upper leathers which are dressed with grease, and which 




Fig. 71. 



is termed whitening, is now often done by machine. 
The operation, including that of " buffing " the grain 
side, is done to some extent by an ingenious revolving 
cylinder of knives, which is given a sort of reciprocating 
motion. Attempts to use it have only been partially 
successful in England, mainly because the shoe manu- 
facturer demands a very fine " face," or density of fibre, 
which is not easily obtained by machine, so that in some 
cases this final operation is carried out by cutting the 
surface of the leather by sharp turned edges of a tem- 
pered steel plate on an absolutely level surface. The 

2 E 



4i8 



LEATHER MANUFACTURE. 



whitening machine in use in America, and to a limited 
extent in England, is shown in Fig. 72. 




Fig. 72. 



Minor operations in leather manufacture, such as 
blacking, glassing, brushing, fluffing, &c, are, of course, 



MACHINERY IN LEATHER MANUFACTURE. 419 

often executed by machinery ; but the design of these 
mechanical aids is simple, and their use so well under- 
stood that no space need be taken up with their 
description. 



Machinery used in Chrome Leather Manufacture. 

The rapid development of this branch of leather manu- 
facture by America has given an impetus to the use of 
machinery that was little anticipated. The necessity for 
keeping the work going in an unbroken stream has 
doubtless had much to do with this, whilst declining 
profits and the high rate of wages paid for certain opera- 
tions have all favoured the engineer. The enormous 
quantities of skins turned out by some of the great 
Philadelphia houses are almost beyond belief, as several 
calculate their output at from two to three thousand 
dozen glazed goat skins per day. It will be seen, there- 
fore, that the difficulty of finding and controlling labour 
for such a trade is very great, and that the business has 
been built up largely by the co-operation of the engineer 
with the practical tanner. 

Machinery used in the Beam House. — It is now 
possible to do almost every operation in what is known 
as the " wet work " by machine, and a brief summary of 
the machines usually employed may be useful as showing 
how independent the large American or European tanner 
is of skilled labour. Taking Patna dried goat skins as 
an example : these are usually well soaked in plenty of 
clean water, to which a little borax may be added with 
advantage, and are often mechanically softened by 
" stocking " or drumming for twenty minutes or so. In 
small yards the work is done by hand by " breaking " 
over the tanner's beam with a blunt knife. 

The next step is to plump the skins and loosen the 
hair, which is done by immersing them in a solution of 
lime and arsenic sulphide. Unhairing is a cheap opera- 
tion, but takes room, so that the use of machines has 



420 



LEATHER MANUFACTURE. 



been introduced with success, and as the same type of 
machine is used later on in the manufacture of chrome 
leather, the illustration at Fig. 73 may be studied with 
advantage. The skins are simply spread in a folded 
condition on each side of the vertical table, which by an 
ingenious motion passes between two revolving rollers, 




Fig. 73. 



both of which are fitted with blunt knives, and revolve 
in different directions. The dehairing is not done very 
clean, but what remains is easily disposed of in a subse- 
quent process. Other types of machines are also favoured 
for unhairing, and an enormous amount of work can be 
done on a modified form of the machine shown for sole 
leather at Fig. 64 (p. 403), whilst there are others equally 



MACHINERY IN LEATHER MANUFACTURE. 421 

good upon the market — such as that shown at Fig. 74. 
The one drawback to the use of machines for this purpose 
is the rather large proportion of damage done to imperfect 
stock. 

After unhairing the goat skins are usually fleshed. 
This process, being a skilled and expensive one, is now 
generally executed by a machine, the principle of which 




Fig. 74. 

is much the same as that shown in Fig. 64 (p. 403) or 
Fig. 74, made by the Turner Co., Peabody, U.S.A. The 
limey and swollen skins are spread on a rubber-covered 
roller, and are passed under a cylinder fitted with knives, 
which are so arranged as to spread the skin outwards 
from the centre. It is as well to remember that very 
imperfect skins are best done by hand, as the rapid 
action of the machine makes it impossible to guard 
against further damage. 



422 LEATHER MANUFACTURE. 

Passing on to deliming, or "puring," as it is techni- 
cally called, it is useful to note that, even here, mechanical 
aid is necessary. Instead of the old-fashioned plan of 
immersing the skins in tubs containing the puring 
solutions, they are now almost always kept on the move 
by agitation in paddle tanks. The time of this very 
disagreeable operation is thereby considerably shortened, 
and the danger of damage to the goods reduced to a 
minimum. After the pure has " brought the skins down," 
i.e. reduced the plumpness caused by the lime, &c, a 
further working called " scudding " is necessary to expel 
the short hair, hair cells, pigment, and lime, soap, fat, 
&c, otherwise the resultant leather would be an inferior 
quality. 

This operation is, in most progressive yards, now done 
by machine, the skin passing over a rubber-covered 
cylinder, whilst slate tools projecting from an upper 
cylinder more or less thoroughly cleanse the grain from 
impurities which, if not removed, would seriously inter- 
fere with the beautiful glazed appearance of the finished 
leather. As scudding is also done on much the same 
class of machine as that for fleshing — in fact, the same 
machine is often used with the insertion of a special 
roller — it is not necessary to illustrate this appliance. 
Goat skins for chrome leather are after scudding thoroughly 
washed in plenty of water and passed on to the actual 
tanning operation. As already explained, this consists of 
immersing the pelts in a solution of bichromate of potash 
and hydrochloric acid for a few hours, and then trans- 
ferring them to a reducing bath of hyposulphite of soda 
and hydrochloric acid. This is followed up by a washing 
in borax or some other alkali to neutralise the acid 
present. The actual tanning is carried out in the paddle 
vat or tumbler — generally the former — already described, 
and the skins after the bichromate bath are struck out 
by a machine of the type shown in Fig. 73. The subse- 
quent processes of " fat-liquoring " and dyeing are 
ordinary operations, and require no special comment in 
a section which only professes to touch on the technique 



MACHINERY IN LEATHER MANUFACTURE. 423 

of the chrome process, as far as it is necessary to elucidate 
the working of mechanical appliances. The striking-out 
operation referred to above is repeated several times as 
required, the final " setting " or permanent extension 
being also given on the same machine. The operation 
is quite simple, the skin being folded down the back 
upon a vertical table which rises between two spiral 
knife-covered rotating cylinders. The effect is to 
thoroughly stretch the skin and to make the desirable 
fine grain. It is easy to use, one man and a boy being 
ample to attend to it, whilst the quantity of work got 
through is very great. Chrome leather shaving is now 
carried out on the machine shown in Fig. 67 (p. 411) ; 
results have proved that chrome leather is absolutely un- 
fitted to hand labour, as the leather is exceedingly difficult 
to cut in any stage, and especially so in the "blue" 
condition, i.e. after the reducing bath. The lighter kinds 
of goat skins cost very little indeed to shave by machine, 
as they are fairly level, and only need reducing towards 
the head of the skin, whilst plenty require no more than 
a slight stroke to level them sufficiently to meet the 
market requirements. 

Finishing Machinery for Chrome Work. — Most of 
the operations in the " dry work " are, in all the large 
manufactories, now executed by machine, as the cost is 
not to be compared with hand labour. The appliances 
used are mainly for softening and polishing, and as each 
skin has to undergo these operations several times, the 
cost even with machinery is fairly great. The dyed 
goat skin is, as we have already shown, after fat- 
liquoring, dyed, "struck," and set out, given a coat 
of glycerine and neatsfoot oil and dried at a high 
temperature. The leather at this stage is hard and 
"tinny," and requires plenty of mechanical work to 
bring it to a saleable condition. After cooling down 
and storing, the skins are usually damped back by 
placing them in damp sawdust for a few hours, and are 
then staked or softened by machinery. In the early 
days of chrome leather manufacture, this process was 



MACHINERY IN LEATHER MANUFACTURE. 



425 



done by drawing the damp skin over a steel plate fixed 
into a wooden post, the knee being the main source of 
power, whilst the hands were used to guide and mani- 
pulate the skin. Another plan was to attach the skin 
to an upright " perch," and, by means of a short crutch, 
which had a steel plate at its extremity, the leather was 
extended in every direction. These crude methods are 
now gradually becoming obsolete, and the machine shown 




Fig. 76. 



in Fig. 75 is one of the best tools for the purpose. The 
action is very simple, the leather being pulled between 
two steel plates; the opening and closing motions of 
the jaws of the machine are quite novelties in leather 
appliances, and are, in fact, somewhat startling to a 
beginner. As the operator has to take the entire " pull " 
of the machine by the pressure of his body to the leather, 
it is well to put a fairly strong man to work it, otherwise 
accidents might occur, or, at least, imperfect skins get 



426 



LEATHER MANUFACTURE. 



hopelessly damaged. There are, of course, other staking 
machines on the market, but the principle is much the 
same. The skins are staked twice, or even three times, 
according to requirements, and are usually glazed after 
each staking. The foundation for the glaze, consisting 
of a weak solution of blood albumen, is usually applied 
with a soft pad to the grain side of the skin, and partially 
or wholly dried before passing on to the machine. The 




Fig. 77. 



flesh side, too, is often " fluffed," i.e. abraded on a wheel, 
much on the principle of the grindstone, with the 
difference that fairly coarse emery powder is the abrasive 
medium. The wheel is of iron, and is shod with a stout 
wooden tyre slightly rounded off, this forming the bed 
for the emery. The dust from the operation is very 
troublesome, but is removed to a large extent by well- 
arranged fans, which draw it away from the operator to 



MACHINERY IN LEATHER MANUFACTURE. 



427 



a suitably placed receptacle. A familiar type of this 
machine is shown at Fig. 76. 

The final operation of glazing is certainly one of the 
most important in the manufacture of chrome kid, and 
involves a great amount of technical skill. The staking 




Fig. 78. 

has had the effect of disturbing the " lay " or pattern of 
the skin, and unless the manipulation is almost perfect, 
the damage done by the rapid action of the polishing 
tool is apt to be very great. Types of machines used are 



428 



LEATHER MANUFACTURE. 



shown at Figs. 77 and 78. These are more generally used 
for glazing vegetable tanned leather, whilst Fig. 79 has 
some special points of excellence, which make it specially- 
suitable for polishing light chrome stock. For goat, 
however, a spring head is used. The frames may be 
either of wood or iron, but the former is claimed to give 
a greater resiliency, which has a beneficial effect on light 




Fig. 79. 



and thin stock. Keference to the illustrations will 
show that the working arm carries a small cylinder of 
glass or agate, which strikes the extended skin with a 
rapid downward motion. The rate of speed varies, 
according to the work and the fancy of the operator, 
from 80 to 120 strokes per minute. The oscillating 
motion caused by this class of machine is great, and 



MACHINERY IN LEATHER MANUFACTURE. 



429 



it should be very firmly fixed, both from above and 
below, if good results are to be obtained, otherwise 
the damage from broken skins and glazing glasses 
is apt to prove rather an expensive item. Probably 
users of this machine would, under any circumstances, 
do well to remember that it is a costly business to 




Fig. 80. 

train operatives for this process, so that only the most 
intelligent men should be selected. 

Before concluding this article on the mechanical 
appliances used in chrome leather manufacture, it may 
be mentioned that a measuring machine has now become 
an indispensable adjunct to a works of any size (Fig. 80) ; 
this is in America and Europe the recognised standard 
for leather-measuring between buyer and seller. The 
skin, in travelling through the machine, affects the 
measuring segments arranged close together, which in 
turn are registered on an index, carefully noted by the 
operator, and marked on the skin. This machine is very 
ingenious, and soon pays for the cost of the outlay as 
every inch of the leather is calculated ; and as all 



430 LEATHER MANUFACTURE. 

chrome leathers are sold by surface measurement, it will 
be seen that it is an absolute necessity that this end of 
the business should be well looked after. 

The most recent idea for measuring the superficial area 
of leather is, however, Connolly's Areameter. The instru- 
ment is simplicity itself, and broadly consists of a set of 
geared wheels, to which are attached a convenient arm 
carrying a pointer. This latter is passed around the edge 
of the skin to be measured, and the result read off on a 
dial attached to the central part of the machine. After 
exhaustive tests, made by Dr. Glazebrook of the National 
and Physical Laboratory, the Areameter has been recog- 
nised as an official standard by the Board of Trade ; and 
at a recent meeting of the Leather Trade Section of the 
London Chamber of Commerce it was recommended to 
the trade " for verifying the measurement of leather and 
skins, and as a means of determining disputes between 
buyer and seller." The machine is put on the market 
by Connolly's Areameter Company, Brighton Chambers, 
Denman Street, London Bridge, London, S.E., and is 
made in various sizes to suit the convenience of users. 

In bringing this article to a close, it may be said that 
no attempt has been made to go fully into the technical 
details of leather manufacture ; the idea has been simply 
to give just a few practical hints to readers who may 
not be familiar with the class of machines mentioned. 
Further particulars relating to the chrome process have 
already been given in another chapter. 



CHAPTER XXXII. 
EMBOSSING LEATHEB. 

Copying Crocodile, Alligator, &c, Skins. 

The art of embossing and otherwise ornamenting leather 
dates back from a very early period, the Egyptians 
having practised the art nearly three thousand years ago. 
At a much later date, namely, about the thirteenth cen- 
tury, the art appears to have been extensively practised 
not only in Italy and Spain, but also in England, many 
specimens of which are still extant. 

The more modern applications of embossed leather have 
been chiefly devoted to leather employed in bookbinding, 
furniture, bags and reticules, purses, and other fancy 
articles ; while still more recently — with the aid of the 
electrotype process — moulds of reptile skins, as those of 
the crocodile, alligator, &c, have been taken, by means of 
which excellent imitations of the natural skins have been 
produced, possessing all the beauty of the original skins 
at a lower cost to the purchaser. 

Embossing machines are made by the following firms 
of engineers : Messrs. Joseph Hall & Co., T. Haley & Co., 
B. and D. Wright, Leeds, and Messrs. Farrar & Young, 
Bramley. The Moenus Machine Co., Frankfort-on-Main, 
also make embossing machines, their latest design, " The 
Altura," being one of the most successful pieces of plant 
ever put on the market for leather work. Messrs. Huxham 
& Brown, of Exeter, have also lately introduced a special 
kind of machine for the purpose, and the writer has seen 
excellent work done by it in a very rapid and effective 
manner. 



432 



LEATHER MANUFACTURE. 



Copying Crocodile, Alligator, &c, Skins by Electro- 
type — It will be readily understood that by the electro- 
type process perfect impressions of the skins of the 
crocodile, alligator, boa - constrictor, and other reptile 
skins can be obtained, and from the copper moulds thus 




Fig. 81. 

produced, leather, previously damped with water, can be 
impressed, and exact copies of the original obtained to an 
unlimited extent. By the same process morocco, seal, and 
other skins are reproduced, and form an extensive and 
greatly increasing branch of leather manufacture, some of 




Fig. 82. 

the results obtained being exceedingly beautiful, the finest 
markings of the grain being reproduced with perfect 
fidelity. Electrotyped copper rollers and plates, bearing 
the pattern of real skins, can now be obtained for the 
manufacture of almost any variety of imitation leather, 
and from each roller several thousand copies may be 



EMBOSSING LEATHER. 



433 



produced. In Fig. 81 is shown the ordinary form of 
embossing and printing machine made by the above- 
named firms, and in Fig. 82 is represented an electrotyped 
copper roller. Small hand-presses are made by the same 




Fig-. 83. 



firms for printing from electrotype plates of real skins up 
to 22 inches by 27 inches, the embossing machine being 
employed for larger surfaces. An illustration of one of 
these hand machiues is shown in Fig. 83. 



2? 



CHAPTER XXXIII. 
FELLMONGERING. 

Classification of Sheep Skins. — Treatment of the Skins. 

Although fettmongering, or removing the wool from sheep 
and lamb skins, is a distinct and separate trade, more 
especially in London, the art is sometimes combined with 
the other operations of the light leather manufacturer in 
some parts of the country, and therefore a brief descrip- 
tion of the method of treating sheep skins by the fell- 
monger will, it is hoped, be useful. Indeed, even if not 
practised by the skinner or manufacturer of light leather, 
he should at all events be conversant with the method 
adopted to free the skins from wool before they come into 
his hands, since this will enable him to judge from the 
appearance of the pelts whether the process has been pro- 
perly conducted or clumsily and carelessly performed ; and 
it is well known that fellmongered skins have frequently 
exhibited unmistakable signs of careless and injudicious 
treatment. Sometimes the skins have been piled in heaps 
to make them sweat, producing incipient putrefaction, by 
which the workman's labour in removing the wool was 
rendered easier ; but the effect of this is that much of the 
substance of the skin is rendered soluble, even in cold 
water, and consequently the skins suffer loss in weight 
when passed through weak lime liquors. 

The London fellmongers, who conduct their business 
upon a very extensive scale, and with every possible care, 
have a high reputation for the excellence of their sheep 
pelts; the same may be said of many of the provincial 



FELLMONGERING. 435 

fellmongers, who know the importance of having their 
workmen well supervised when conducting operations re- 
quiring skill and judgment. 

Classification of Sheep Skins. — The skins of sheep 
slaughtered in Great Britain are divided into large, medium, 
and small skins, and may be arranged under the following 
heads : 1, Lincoln, Leicester, Cotswolds, and other large 
kinds weighing from 9 st. and upwards ; 2, Southdowns, 
Scotch, and other skins of medium weight ; and 3, Skins 
of small Welsh mountain sheep, foreign sheep slaughtered 
in this,, countrjr, and the numerous varieties of lamb skins. 

The larger stout sheep skins are usually split by machi- 
nery, the grain side being used for skiver, and the Jlesh 
side employed in preparing buff or " shamoy " leather 
(oiled leather), and in the manufacture of parchment. A 
considerable number of the larger heavy sheep skins are 
tanned into what are called basils, the West of England 
being specially famous for its oak-tanned basils, while 
Scotland and some of our northern counties also produce 
vast quantities of basils, which are tanned with larch bark, 
and are much used by saddlers for lining the heavier 
leathers. It is believed that the aromatic odour imparted 
by larch bark gives to the leather prepared with it similar 
attributes to those generally accorded to Russian leather. 
Considerable numbers of the larger sheep skins are taived 
with alum and salt. 

The medium weight skins are chiefly tanned with sumach 
for roans, a variety of leather somewhat resembling mo- 
rocco, but wanting its peculiar grain. These skins are 
also used for preparing leather used for the rollers of cotton 
spinning machinery. The small sheep skins of Wales and 
Scotland and the mountainous districts of England are 
employed in the art of tawing, for gloves, shoe linings, and 
numerous other purposes. Cape sheep and lamb skins are 
very extensively used by the manufacturer of light leather, 
being nearly equal to goat skins, and the leather prepared 
from them is largely used for making dog-skin gloves, and 
many kinds of coloured gloves exposed for sale as kid gloves. 

Treatment of the Skins.— The skins are first thoroughly 



436 LEATHER MANUFACTURE. 

washed in water, to cleanse them from filth and dirt, after 
which they are spread out flat, one above another, with the 
flesh side upward. Each skin is then painted over with a thick 
cream of lime on the flesh side. The skin is next doubled, 
with its wool side outward. The skins are then piled in 
heaps of about twenty skins, and allowed to remain un- 
disturbed from twenty-four to forty- eight hours, at the end 
of which time the wool has become loosened, and the 
workmen, unfolding the skins one by one, proceed to pull 
the wool off, keeping the various qualities separate. When 
the wool is removed, the pelts are thrown first into water, 
and afterwards into a pit containing a weak lime liquor, 
from which they are drawn once or twice a day, the 
liquor being stirred or plunged each time before replacing 
them in the pit, so as to equalise the action of the lime. 
They are treated in this way for the first three or four 
days, after which they are subjected to a stronger lime 
liquor, being repeatedly drawn daily as before, and by the 
end of from seven to ten days, according to the season, the 
skins are ready for unhairing — that is, removing the hair 
from the shanks and other parts left after the first opera- 
tion. In the early part of summer, while the wool is very 
short, the skins, after being shorn of the wool, are treated 
somewhat differently. They are first thrown into water to 
remove the filth, after which they are placed in lime liquor, 
being lifted once or twice a day as before, and then sub- 
jected to stronger lime liquors, in which they remain 
until the wool readily yields to the touch, when it is 
removed in the usual way. By this treatment the value 
of the wool is impaired, but this in the case of shorn sheep 
is of little consequence. The wool is disposed of to the 
icoolstaplers, who cleanse and prepare it for the woollen 
manufacturers. 



CHAPTER XXXIY. 

PARCHMENT, VELLUM, AND SHAGREEN. 

Preparation of Parchment and Vellum. — Skins for Drumheads.— Sha- 
green. — Fish Skin, or Fish Shagreen. 

Preparation of Parchment and Vellum. — The employ- 
ment of this substance for writing purposes is of very early 
date, and is said to have been invented by Eumenes, King 
of Pergamos, in Asiatic Turkey, about two hundred years 
before the birth of our Lord. In ancient times it was 
known as pergamena, and was used, on account of its 
durability, for writings of great importance, and as a sub- 
stitute for the papyrus, or writing paper of the ancient 
Egyptians. There are two principal varieties of this sub- 
stance, which are known in commerce under the names of 
parchment and vellum, the latter being prepared from 
the skins of calves, kids, and still-born calves and lambs, 
and the former from sheep and goats. In the preparation 
of parchment and vellum, the manipulation of the skin is 
much the same, but in the latter case somewhat greater 
care is necessary owing to the very delicate nature of the 
skins to be treated. 

The skins are washed, limed, unhaired, and fleshed, 
again well washed, and then stretched either on hoops or, 
in large manufactories, upon a wooden frame called the 
herse. This is formed of two uprights and two cross- 
bars, well joined together by mortising, so as to form a 
strong frame to be fixed to a wall. The four bars are 
perforated all over with a number of holes, to receive 
tapering boxwood pegs, in each of which is a hole, as in 
the pegs of a violin, to receive the strings which are 



43? LEATHER MANUFACTURE. 

employed in stretching the skin. A wooden shelf is fixed 
above the kerse to support the tools used by the workman. 
To stretch the skin, skewers of various sizes are used, 
according to the size of the piece of skin to be secured. 
Six holes are made in a straight line to receive the larger, 
and four to admit the smaller pegs or skewers. These 
small slits are made with a tool like a carpenter's chisel, 
and the exact size to admit the skewer ; the string round 
the skewer is fixed to one of the bolts of the frame, which 
are turned round by means of a key resembling a piano- 
forte tuning key. The skewer is threaded through the 
skin while taut. Being thus prepared and the skin 
well softened with water, the workman stretches it power- 
fully hj means of the skewers ; he attaches the strings to 
the skewers, and fixes their ends to the pegs, which he 
then turns with the key, taking care not to allow any 
wrinkles to be formed. It is usual to stretch the skin 
more in its length than in its breadth. He then takes a 
fleshing tool, which is a double-edged knife made fast in 
a double wooden handle, in both hands, and scrapes or 
shaves the skin from above downwards, by which he 
removes the fleshy matters, which are afterwards collected 
for glue-making. The herse is then turned round from 
the wall, and the grain side of the skin is then scraped 
With the tool in an inverted position, so as not to cut the 
grain of the skin. 

The herse is again turned, and the flesh side of the 
skin is next dusted over with sifted chalk or slaked lime, 
and is then rubbed over in all directions with a large 
piece of pumice-stone, previously rubbed flat upon a sand- 
stone ; the moisture in the skin is quickly absorbed by the 
chalk. When sufficiently rubbed on the flesh side, the 
skin is again turned, and the grain side rubbed in the 
same way, but without the use of lime or chalk. The 
above operation is generally applied only to the better 
qualities of parchment or vellum. The skin is then allowed 
to dry upon the frame in the shade, care being taken to 
avoid sunshine and also frost. In very hot and dry 
weather the skin is damped with a wet cloth, to prevent 



PARCHMENT, VELLUM, AND SHAGREEN. 439 

it from drying too quickly ; the skewers are tightened 
after each damping. 

When quite dry, the chalk powder is removed by rub- 
bing the skin with the wool side of a piece of lamb skin. It 
is of great importance in pumicing not to injure the texture 
of the skin. If the skins are greasy they must be immersed 
in the lime-pit for a week or ten days, then stretched 
again upon the herse, and afterwards handed to the scraper, 
who here employs an edge tool of the same shape as the 
fleshing knife, but larger and sharper. He mounts the 
skin upon a frame like the herse, but extends it merely 
with 'cords, without skewers or pegs, and supports it 
generally upon a piece of raw calf skin strongly stretched. 
The tail of the skin being placed towards the bottom of 
the frame, the workman pares off with a sharp knife any 
considerable irregularities, and then scrapes the outside 
surface obliquely downwards with the proper tools till it 
becomes perfectly smooth. Any remaining irregularities 
are removed with the pumice-stone. This operation is 
performed by laying the rough parchment upon an oblong 
plank of wood in the form of a stool, the plank being 
covered with a piece of soft parchment stuffed with wool, 
forming a cushion, for the grinding operation. It is the 
grain surface only that requires pumicing. The famous 
Strasburg vellum is prepared with very fine pumice- 
stones. 

Skins for Drumheads.* — The skins for drumheads are 
prepared from the skins of calves, and for kettledrums 
from asses' skins. These are treated in the same way as 
above. Parchment is usually coloured only green by the 
following process : In five hundred parts of rain water 
boil eight parts of cream of tartar and thirty parts of crys- 
tallised verdigris ; when this solution is cold, pour into it 
four parts of nitric acid. Moisten the parchment with a 
brush, and then apply the above liquid evenly over the 
surface. Lastly, the necessary lustre may be given with 
albumen (white of eggs), or mucilage of gum arabic. ( Ure.) 

* The skins for banjos and tambourines are generally prepared from the 
skins of still-born calves. 



44° LEATHER MANUFACTURE. 

The sieves used in powder-mills for granulating the 
gunpowder are made from parchment prepared from hog 
skins. English vellum is frequently made from split sheep 
skins. 

Shagreen. — This name is given to a peculiar kind of 
parchment, and is prepared from the skins of the horse, 
wild ass, and camel, as follows : The skin is freed from 
its hair and cuticle by being long soaked in water, and 
after dressing with the currier's fleshing knife is sprinkled 
over, whilst still wet and stretched, with the seeds of a 
species of Chenopodium, which are imbedded in it by strong 
pressure, and in this state it is dried. The seeds are then 
shaken off, and the surface is rubbed or shaved down nearly 
to the bottom of the seed-pits or indentations ; it is next 
soaked in water, by which the skin swells, and the recently 
depressed surfaces rise into a number of minute promi- 
nences ; it is then tawed with alum, and is lastly dyed and 
smoothed off, or saturated with mutton tallow. Black is 
given to the skin by means of galls and copperas, blue 
with a solution of indigo, green with copper filings and 
sal ammoniac, and red with cochineal and alum. Sha- 
green was formerly extensively used for covering the 
cases of watches, spectacles, and surgical instruments. 

Fish Skin, or Pish Shagreen. — This is prepared from 
the skins of certain species of shark, which are covered 
with horny projections in lieu of scales. The skins are 
stretched upon frames and dried, in which condition they 
are sent to market. When deprived of the projecting 
spines they are dyed and used for covering small boxes, 
tubes of small telescopes, &c. 



CHAPTER XXXV. 
GUT-DRESSWG. 

Preparation of Cattle Intestines : Continental Method. — Goldbeaters' Skin. 
— Lathe Cords. — Cords from Sheep Intestines. — Cords for Tennis Bats, 
&c. — Whipcords. — Gut Strings for Musical Instruments. 

The art of gut-dressing consists in separating the mus- 
cular coat of the intestines of certain animals from its 
external or peritoneal covering, and from its internal 
lining, or mucous membrane, and is divided into two 
distinct branches : 1, the preparation of the intestines of 
oxen and cows to be used in the preparation of alimentary 
substances, as sausages, polonies, &c. ; and 2, the prepara- 
tion of the intestines of sheep for the manufacture of 
cords or strings for musical instruments and various other 
purposes. 

Preparation of Cattle Intestines : Continental Me- 
thod. — Dussauce describes the workshop of the gut- 
dresser as "a room about 20 feet long, 16 feet wide, and 
12 feet high, with four windows. Around the sides of 
the room are ranged casks holding about sixty gallons 
each, and in the middle of the floor are fixed wooden 
stages for attaching hooks. A well is usually sunk in the 
yard to receive the waste matters of the factory." 

There are eleven distinct operations in gut-dressing, the 
first of which is — 

Scouring. — As the small intestines of oxen and cows are 
received from the slaughter-house they are steeped in water 
to moisten and smooth them, so that the knife may slide 
easily over their surfaces. One end of the intestine is 
now tied into a kind of knot round a hook to one of the 



442 LEATHER MANUFACTURE. 

stakes in the centre of the room, the hook heing ahout six 
or seven feet above the floor. The workman then grips 
the depending portion between the forefinger and thumb 
of his left hand, and gradually slides the hand down along 
the whole length of the intestine, and follows its motion 
by passing a knife, held in the right hand, over the sur- 
face, to separate the fat as far as possible from the outer 
coat. Another portion of gut is treated in the same way, 
and so on until the entire caskful has been cleaned. Any 
portions which have been accidentally cut by the slaughter- 
man are laid aside. The fatty matter scraped from the gut 
is well washed and melted, or rendered, as it is termed, and 
disposed of to the soapmaker. 

Turning Over. — The intestines are next washed in a 
large cask half filled with water, and the workman next 
proceeds to turn them inside out by introducing a thumb 
into the interior of each, and working the gut upon it 
with the fingers until the whole length is inverted. A 
number of the pieces are then tied together at their ends 
with a cord attached to the edge of the cask, and when a 
sufficient number of inverted intestines are thus secured 
they are ready for the next operation. 

Putrid Fermentation. — The object of this process is to 
decompose the mucous lining and other parts which have 
to be separated from the middle coat of the intestine, and 
if the operation is not conducted with great care the whole 
substance of the gut will become softened and rendered 
useless. The putrefaction is allowed to proceed for two or 
three days in summer and from three to eight days in 
winter, and it is known to have progressed far enough 
when bubbles of gas are seen to arise from the surface of 
the intestines. 

Scraping. — The pieces are first untied, then soaked in a 
tub half full of water. The workman next proceeds to 
remove the decomposed mucous membrane (which is now 
outward), by scraping it off with his thumb nails until it 
is completely removed, and he facilitates the process by 
occasionally dipping the pieces in water. 

Washing. — The intestines are put into a tub nearly full 



GUT-DRESSING. 443 

of clean water, being stirred about several times every day, 
the water being changed two or three times a day, and 
the operation continued until the water comes from them 
perfectly clear and free from smell. 

Inflation. — "When thoroughly cleansed by the foregoing 
operations, one end of each piece is tightly tied by a piece 
of string. The workman next introduces into the open 
end a hollow cylinder of cane or reed about 5 inches long, 
and after making this air-tight by pressing the gut tightly 
round it, he applies his mouth to the cane tube and inflates 
the gut by blowing into it. He then ties the end below 
the ttfbe, and the piece is ready for drying. 

Drying. — As soon as all the pieces are filled with air 
they are conveyed to the drying place, where they are 
laid out separately upon horizontal poles placed about 
5 feet from the ground, and here they are left until dry. 
When thoroughly dry they are taken down, cut across 
with scissors as near the ligatures as possible. They are 
next pressed and flattened with the hand to expel the 
air. 

Measuring. — The dried pieces are next sorted into dif- 
ferent sizes, according to the purpose for which they are 
to be used ; they are then collected into bundles, and hung 
in a damp place previous to being submitted to the next 
process. 

Sulphuration. — When sufficiently damp, the pieces are 
next exposed to the fumes of sulphur, in a chamber about 
5 feet square and 6 feet high. They are first strung on 
sticks, and if not sufficiently moist they are sprinkled over 
with water from a brush ; they are then suspended across 
the upper part of the chamber to the number of about 
100 bundles. About one pound of flowers of sulphur is then 
put into an earthen dish placed on the floor of the room, 
and upon this red-hot cinders are laid ; the door is then 
quickly closed, to retain the sulphur fumes within the 
apartment, and every aperture is secured by luting or by 
glueing pieces of paper over them. After a few hours the 
door is opened and the fumes allowed to escape, when the 
pieces are found to be bleached and deprived of all objec- 



444 LEATHER MANUFACTURE. 

tionable odour. While still damp, they are twisted into 
hanks, packed with camphor, and are then ready for 
market. 

Goldbeaters' Skin.— This is prepared from the external 
or peritoneal coat of the caecum or blind gut of neat cattle. 
The workman separates and turns over the part which 
encircles the junction of the pouch with the rest of the 
intestines, and draws it off, inverted, from the other coats 
to the length of 25 or 30 inches. It is then soaked for a 
short time in a weak potash liquor, and is next cleaned 
by scraping with a knife upon a board ; it is then soaked 
in water, and afterwards stretched upon a kind of frame 
from 40 to 50 inches long and 11 inches wide. This frame 
consists of two uprights held together by two cross-bars, 
having longitudinal grooves 2| lines in width. The outer 
surface of the membrane is placed in contact with the 
upper part of the frame, and it is stretched in every direc- 
tion, after which it is glued to its rim. Another mem- 
brane is then stretched over the first, with its outer surface 
upward, and secured by glueing round its edges. When 
dry, the membranes are separated by passing a knife 
along the grooves. Each strip is then glued upon a 
similar frame, but without grooves, and is washed over 
with a weak solution of alum, made by dissolving one 
ounce of alum in two quarts of water. When dry, the 
surface is wiped over with a sponge dipped in a strong 
solution of fish-glue in white wine, flavoured with clove, 
nutmeg, or camphor. When this is dry a coating of 
white of eggs is applied, and after again drying each strip 
is cut up into pieces 5 \ inches square, which are then 
smoothed under a press and afterwards made up into 
leaves. 

Lathe Cords.* — These are prepared from the intestines 
of horses, cleansed and prepared as before described, and 
the pieces are cut into bands or strips of equal width in 
the following way : A wooden ball, furnished in its lower 
part with four equidistant cutting blades, is fixed by a 

* Gutta-percha and vulcanized india-rubber have greatly superseded 
gut cords for lathes. 



GUT-DRESSING. 445 

wooden upright to a bench. The end of an intestine is 
then drawn over this ball, and as the gut is pulled down- 
ward it becomes divided into four equal strips. From four 
to eight of these strips, according to the thickness of cord 
required, are tied with a peculiar knot to one end of a 
stout piece of cord ; the end is passed round a peg inserted 
into a hole in a solid post, to the side of which a number 
of pegs are attached. About ten yards from this post is 
another post, also provided with pegs ; over one of these 
latter the middle strip of the cluster is bound, the other 
end being brought back and attached to the first peg by 
anoth'er knotted cord. The tied ends of the strips are then 
attached to the wheel by a hook connected with a whirl, 
which is made to revolve until the strips are sufficiently 
twisted. The twisted end is then kept stretched by attach- 
ing it to the peg, and any projecting filaments are cut off. 
After stretching some time, the cords are twisted again, 
and the third and fourth time this is done by hand, being 
rubbed with and drawn through a bunch of moistened 
horsehair each time after twisting, and again stretched 
out between the two posts. If the cord is not smooth and 
even when the twisting is completed, it is rubbed with a 
piece of dog skin. The cord is then dried, but some manu- 
facturers expose it to the fumes of sulphur. The ends are 
now cut off and the cord is rolled into a coil. 

Cords from Sheep Intestines.* — It is important that 
the intestines should be fresh — that is, free from decom- 
position. They are first cleansed from fcecal matter and 
washed ; they are then taken to the workshop, where they 
are soaked in a tub of water and deprived of adhering fat. 
The smaller ends are then tied together and laid on the 
edge of the tub, while the remainder are allowed to steep 
in the water for several days, the water being frequently 
changed. The peritoneal and mucous coats are then re- 
moved by placing the intestines on a bench, which slopes 
towards the rim of the tub, and the surface is scraped with 
the back of a knife-blade to separate the membranes to 
the width of about half the circumference. This is done 
* Erroneously called catgut. 



446 LEATHER MANUFACTURE. 

by pulling it off in pieces from the smaller end of the 
intestine towards the larger end. The gat is next soaked 
in water for twenty-four hours, and afterwards scraped 
clean upon the bench with the rounded back of a knife. 
About 8 feet of the larger ends are now cut off for use by 
the sausage-makers ; the remainder are cut into lengths 
and stratified with salt, which is termed curing. After 
remaining in the salt for some days they are soaked in 
water for a night, and next day they are immersed in a 
ley composed of pearlash 8 oz. dissolved in water 4 gal- 
lons. The ley is poured over the intestines, and every 
two or three hours the liquor is poured off and the intes- 
tines are examined to ascertain if they have been suffi- 
ciently acted upon by the alkali. They are next drawn 
several times through a brass thimble open at both ends, 
and then sorted, according to their sizes, for the different 
purposes to which they are to be applied. 

Cords for Tennis Bats, &c. — These are generally made 
from intestines of inferior quality, or such as have been 
stained by incipient putrefaction. The pieces while still 
moist are sewn together with strips of the outer mem- 
brane, or filandre, each junction being cut obliquely, so as 
to make it level and strong. Three or four of these intes- 
tines are thus attached by strings to the whirl, and are 
twisted as usual, after which the cord is smoothed and 
deprived of moisture by the workman's hand ; it is then 
stretched for a time, when it is again twisted and rubbed 
with the bunch of horsehair. The inferior kinds of cords 
are prepared by twisting one gut along with two or three 
lengths of the outer membrane. 

Whipcords. — These are made from intestines of good 
quality, prepared as before, each end being twisted sepa- 
rately, since these cords are seldom made from two intes- 
tines sewn together. The cord is " sulphured" once or 
twice, and is then smoothed and dried, after which it is 
coiled in certain lengths for sale. 

Gut Strings for Musical Instruments. — Of all the 
purposes to which the intestines of animals are applied, 
none is so important as their conversion into what is 



GUT-DRESSING. 447 

commonly called catgut, for the strings or cords of 
" stringed. " instruments, including the whole violin 
family and the harp. From the earliest period Italy has 
been most famed for the production of violin strings of 
the finest quality, a reputation which she has main- 
tained to the present day; and though a vast number 
of these strings are made both in England and various 
parts of the Continent, the " Roman strings," as they are 
called, are justly held in the highest estimation. It is a 
well-known fact that the membranes of lean animals are 
much tougher than those of animals in a higher condi- 
tion, and it is to this fact that the superior quality of the 
strings made in Naples is due, since the sheep from which 
the raw material is obtained are exceedingly small and 
also lean. The strings made from the intestines of the 
fat sheep of the London market are well known to be 
greatly inferior in toughness and durability to those of 
Neapolitan make ; and from the frequency with which the 
former break when being tuned up to concert pitch, they 
often cause much disappointment, irritation, and incon- 
venience to musicians. 

Treatment of the Intestines. — The intestines being 
cleansed as before, are steeped in the potash leys (clarified 
with a little alum), progressively stronger each day, for 
four or five days, until they are sufficiently swollen and 
bleached. They are then passed through the thimble, and 
again cleansed in the ley, after which they are washed, 
twisted, and sulphured for two hours, which operation is 
sometimes repeated several times. They are next polished 
with horse-hair cords and dried. The strings are known 
to be sufficiently dried when one of the strands, upon being 
removed from its peg, shows no disposition to curl, but 
remains perfectly straight in the position in which it is 
held. When the strings have reached this point they 
are rubbed over with olive oil, cut at the ends, and 
coiled up. 

The violin fourth strings, which are covered with plated 
copper wire, are neither sulphured nor oiled. The string 
to be wire-covered is cut off to the length of 1\ yard ; one 



448 LEATHER MANUFACTURE. 

of its ends is attached to the hook of the wheel and the 
other to the ring of a whirl, which keeps the string 
stretched by means of a weight at the end of a cord 
fastened to it, and passing oyer a pulley. The wire is 
then fastened around the string close to the whirl, and as 
the wheel is made to revolve the string and the whirl 
turn with it. The workman supports the string with his 
left hand, and the wire passing through his right hand 
is made to revolve around it in close spiral turns until it 
is entirely and equally covered (Dussauce). The utmost 
skill and dexterity on the part of the workman are 
required for the manufacture of violin and harp strings, 
which he can only acquire by extensive experience and 
care. 



CHAPTEE XXXVI. 
GLUE-BOILING. 

Treatment of Glue-piecos, &c. — French Glue. — Parchment Glue. — 
^ Size. — Glue AVaste. 

Treatment of Glue-pieces, &c. — The glue -pieces and 
other animal matters used in the manufacture of glue are 
put into a large tank containing milk of lime, in which 
they remain for about two weeks, the lime being renewed 
several times. They are then taken out, with the lime which 
adheres to them, and spread out in a layer two or three 
inches thick upon a sloping pavement to drain and dry, 
being turned over by means of prongs several times a day. 
The action of the lime destroys all the tissues, blood, &c, 
rendering them soluble, by which they become separated 
from the glutinous matter, which is thereby put into a 
condition to dissolve more freely in hot water. By ex- 
posing the lime to the action of the air, it loses its caus- 
ticity by attracting carbonic acid, and is thus prevented 
from acting injuriously upon the glue when the mate- 
rials are boiled. The glutinous matters are next put into 
baskets and washed in a stream of water, after which 
they are placed, while still wet, in a flat-bottomed copper 
boiler, furnished with a perforated false bottom to pro- 
tect the animal matter from being burnt by the heat of 
the fire. 

-■First Boiling. — The copper is filled about two-thirds 
with soft water, when the washed material is introduced and 
piled up above the flange of the boiler ; the fire is then 
kindled, and as the heat increases the material sinks into 
the liquid, and after a few hours becomes completely 
immersed in the liquid. During this time the contents 

2G 



45° LEATHER MANUFACTURE. 

of the boiler are frequently stirred, and the whole boiled 
gently. 

Dratoing off the Liquor. — The liquid is drawn off by a 
tap connected to the bottom of the boiler, and beneath its 
false bottom, and the first, second, and third liquors, re- 
presenting different qualities, are reserved for glues of 
proportionate value, the product gradually decreasing in 
value as the boiling progresses. It has been proved that 
gelatine undergoes various changes of condition after it 
is dissolved by continued boiling-, and it should therefore 
be drawn off whenever it is sufficiently strong to form a 
clear gelatinous mass on cooling, and which will cut into 
tolerably firm slices with a thin wire. This is readily 
ascertained by putting a little of the liquor in a small 
vessel and exposing it in the air to cool, when in the 
course of a few minutes it should gelatinise ; if such is 
not the case, the boiling must be continued for a longei 
period. As soon as the proper condition of the liquor is 
reached the fire is checked, and the contents of the boiler 
allowed to settle for about fifteen minutes. The tap or 
stopcock is then turned a little and all the liquor allowed 
to flow into the settling copper, situated below the first, 
and which is immersed in a hot-water bath to keep the 
fluid hot. 

Gelatinising. — After three or four hours the clear liquor 
is run off into a series of square wooden boxes slightly 
narrower at the bottom than at the top. The bottoms of 
these boxes are cross-grooved to regulate the size of the 
squares of glue. These boxes are placed very level on 
the stone floor of the apartment, which must be rendered 
very clean, so that in the case of leakage the glue may be 
recovered. The liquid glue is poured into the boxes 
through a funnel, provided with a filter-cloth, until it 
reaches the upper rim of each box. The apartment re- 
quires to be very dry and cool to aid the solidification of 
the glue. 

Cutting. — If the boxes have been filled overnight, the 
glue will generally be sufficiently firm to cut on the 
following morning. The boxes are then removed to a 



GLUE-BOILING. 451 

well- ventilated upper loft, in which the air is admitted 
from all points ; they are then carefully turned upside 
down upon a table, previously moistened to prevent the 
glue from sticking to it. The glue is then loosened from 
the sides of the boxes by passing a moist long-bladed 
knife round the inner sides. The block of glue is first cut 
into slices horizontally by means of a thin brass wire 
stretched in a frame like that of a frame-saw, and the 
cuts are guided by rulers placed at proper distances to 
suit the required thickness of the glue cakes. The 
square cakes are formed by cutting with a moist knife 
through the lines formed by the grooves in the bottom of 
the box. 

Drying. — The gelatinous squares are next lifted very 
carefully and laid upon nets stretched upon wooden 
frames ; as each frame is filled another is placed above it, 
to be filled in its turn, and so on. The frames are set 
over each other, with a space of about three inches be- 
tween, and upon small wooden pegs fitting into holes in 
uprights fixed round the room, so that the air may have 
free access on every side. The frames, supported by 
the wooden pegs, slide to and fro like a drawer, which 
enables the workmen to shift them from time to time, 
to turn the cakes over, which is done two or three times 
each day. 

There is no detail in the manufacture of glue which is 
so uncertain as that of drying the jellified material, espe- 
cially in the earlier stages ; if the temperature of the 
atmosphere should rise above a certain degree, the gelatine 
may run, and trickle through the netting upon the cakes 
beneath, or may become just sufficiently soft to firmly 
attach itself, when drying, to the netting, rendering it 
necessary to plunge the net into boiling water to discon- 
nect the cakes ; and even if these untoward difficulties do 
not arise, the augmented temperature will render the cakes 
so soft as to put them out of proper shape. Again, if the 
gelatine become frozen, the cakes are liable to crack, and 
thus necessitate remelting. In damp and foggy weather 
the glue is liable to become mouldy on the surface, while 



452 LEATHER MANUFACTURE. 

if the air be too dry and hot, it is likely to dry too rapidly, 
causing it to crack in numerous places. The only remedy 
for the above evils is to keep the flaps of the drying-room 
windows closed as occasion may require, and if possible to 
conduct the operation in the spring or autumn. When 
the cakes have been dried upon the nets they may still 
retain a certain amount of elasticity, which would render 
them unsaleable ; when such is the case they require to be 
dried in a stove by moderate heat. 

Glossing. — In order to give the cakes the bright glossy 
surface which is characteristic of this article, the dried 
cakes are dipped one by one into hot water for an instant, 
and they are then brushed over with a brush, also dipped 
into hot water. The cakes are then spread upon a hurdle, 
and are afterwards placed in the stove-room if the weather 
be damp, until the surfaces are perfectly dry, when they 
are ready for packing into casks for sale. 

Second Boiling. — After the lirst liquor has been removed 
as before described, fresh water is put into the copper, 
and the boiling continued until the mass has a gelatinous 
appearance, when the liquor is drawn off by the stopcock 
as before, and is then submitted to the same operations as 
the first liquor. 

Third Boiling. — The remaining grounds are next treated 
with a fresh supply of water, or weak liquors containing 
some gelatine. The bottoms, or grounds, are afterwards 
taken out of the boiler and placed in bags, which are 
submitted to pressure to extract as much of the liquor as 
possible. 

The above three boilings yield three different qualities 
of glue. The lirst is pale coloured, and is the most suit- 
able for uniting all kinds of woodwork. The second and 
third qualities are often preferred, however, by workmen 
who innocently believe that a dark-coloured glue has the 
strongest adhesive power. 

French Glue. — This is made from the gelatine of bones. 
The bones are first treated with hydrochloric acid, which 
dissolves the phosphate of lime, leaving the gelatinous 
substance of the bones in a soft and soluble condition, 



GL UE-BOILING. 45 3 

which is afterwards dissolved and converted into glue. 
The product is, however, of very poor quality, and is 
soluble in cold water — a proof of its inferiority. Good 
glue does not dissolve in cold water, but is merely soft- 
ened by it. 

Parchment Glue is prepared from the shreds or shavings 
of parchment, vellum, white leather, &c, by boiling in 
water; it is nearly colourless, and without odour. 

Glue of inferior quality may also be prepared from the 
tendons and other offals of the slaughter-house, but the 
refuse of the tanneries, such as the ears of oxen, calves, 
sheep^ &c, form a better glue stock, while the parings of 
ox and cow hides are the best of all materials for glue- 
making. 

Size. — Ordinary size, such as is used in plastering and 
other coarse work, is prepared from the same materials 
as common glue, but the liquid is not evaporated to so 
great an extent as is requisite for the latter substance ; 
being always kept in a soft condition so as to be readily 
soluble in water, the gelatine solution is made of such a 
strength that, when cold, it will set into a firm jelly, or, as 
it is called, size. Other varieties, of a superior quality, 
are, however, prepared for manufacturing gelatine, for 
thickening soups, and other domestic purposes, from se- 
lected materials, such as calves' pates, &c. In preparing 
this quality of size greater care is taken to remove the 
lime than is necessary in ordinary glue-making, and to 
accomplish this the pieces, after liming, are treated in a 
very dilute solution of hydrochloric acid. The boiling is 
usually effected by means of steam-heat, and the liquid, 
when in the proper condition, is either run out into small 
casks for sale, or into large vats, and when cold is broken 
up and packed in casks. For making the finest qualities 
of size, for use as an article of diet, steam jacket-pans are 
employed in boiling the materials. The size used by 
paper-makers is of the best quality manufactured by 
ordinary glue makers. 

Glue Waste. — The refuse left after the final boiling is 
thrown aside for manure. Since it rapidly decomposes, 



454 LEATHER MANUFACTURE. 

however, it soon becomes offensive, rendering its removal 
exceedingly unpleasant after about twenty-four hours. 
MM. Leblanc, of Lyons, have discovered in this refuse 
matter a considerable quantity of a fatty substance, which 
can be used in the manufacture of soap as well as for 
lubricating purposes. It can be extracted by means 
of bisulphide of carbon, petroleum, benzol, &c, but sul- 
phuric acid is recommended as being cheaper and safer 
in use. A vessel capable of holding from 50 to 100 
gallons, heated by steam or otherwise, may be used for 
the purpose. 

For 220 lbs. of refuse, 11 gallons of water are taken and 
acidified with sulphuric acid, till it stands at about 6° to 
8° Baume. The whole is then boiled, and after a suitable 
mixing has been effected, sulphuric acid of 48° Baume is 
poured in by degrees, until a complete saturation has 
taken place, or until the fatty substance has been sepa- 
rated. The quantity of the 48° acid varies according to 
the greater or lesser proportion of gelatine in the waste. 
It averages about 10 per cent. This operation lasts about 
two or three hours. 

The mass is then placed in cloths, each holding about 
35 to 45 lbs., and these are placed under a hydraulic press 
with a division between each cloth. The fluid obtained is 
directed into receptacles, and the fatty substance on the 
top is removed. The pressed cakes remaining are very 
rich in nitrogenous substances, which are as effective for 
manuring purposes as the refuse in its original form. The 
cakes are dried, and can then be stored until required for 
use. 



CHAPTER XXXVII. 

UTILISATION OF TANNERS' WASTE 

Spent Jan.— Guest and Court's Process. — Hide and Skin Cuttings. — 
Hair Waste. — Lime "Waste. — Glucose in Leather. 

Spent Tan. — When we reflect upon the vast quantity of 
tan refuse that is annually produced in the United King- 
dom we cannot be surprised that many efforts should be 
made — even by persons outside the trade — to turn this 
waste material to practical account. It had long been the 
practice at some tanneries to employ it when dried, or 
partially dried in the air, as fuel ; again, a considerable 
quantity has been, and is now, used as manure. In 1852 
Mr. J. B. Hoyt, of New Jersey, conceived the idea of burn- 
ing wet spent tan in a detached brick furnace, and 
succeeded in obtaining sufficient heating power to drive 
his machinery by its agency, and practically adopted this 
method of utilising the waste tan from that time. The 
great success of his system created quite a revolution in 
the American tanneries, and its adoption became general. 
Ill this country Messrs. Huxham and Browns have con- 
structed a tan-burning boiler, which, we believe, has 
proved very efficient. 

Another and still more important use for spent tan — 
should any of the patented processes prove successful — is 
in the conversion of the fibrous waste into pulp for paper- 
making. This would doubtless be the most profitable 
purpose to which the material could be applied if an 
effectual and economical method of pulping and bleaching 
could be introduced. In 1881 Messrs. Guest and Court 
obtained a patent for converting waste tan into pulp for 



456 LEATHER MANUFACTURE. 

paper making, the abridged process of which is given 
below. 

Guest and Court's Process. — The spent tan is put into 
a hopper, from which it gradually passes between, and is 
crushed by, two or more revolving rollers, the object of 
which is to open the fibres and break up the knots of the 
waste material. The inventors prefer to feed the rollers 
with the spent tan in a semi-dry state. The fibres being 
thus separated to some extent, the mass is introduced in 
convenient quantities into a rotary boiler or agitator 
containing a solution of caustic soda in the proportion of 
one-twentieth part to the water used. The boiler is then 
closed, steam admitted, and the whole agitated by means 
of arms or cutters in the interior, and the separating or 
opening (disintegrating) process maintained. The mass 
may be washed in the boiler or in a separate vessel. 
When it is desired to bleach the mass, it is subjected to 
the action of bleaching materials. In the event of any 
such process becoming really practicable, it would then be 
worth while to keep spent bark separate from valonia, &c. 

Hide and Skin Cuttings. — These are commonly called 
" glue pieces," and are disposed of to the glue manufac- 
turers, but their value depends greatly upon the care 
taken to preserve them from decomposition. This is more 
especially important when they are to be used for making 
size for paper-making, since the least smell or "taint" 
would be noticeable in the paper, and greatly reduce its 
value. It is also very important that the fine glues used 
in bookbinding should be free from objectionable smell ; 
therefore it will be well understood that the value of the 
glue pieces will depend upon their not having undergone 
decomposition while in the possession of the tanner. 
When it is borne in mind that glue pieces which have 
become tainted can only be employed for making what is 
known as carpenters' glue, their preservation from decom- 
position should be a matter of great consideration in order 
to maintain their proper value. 

Respecting the preservation of glue pieces, Jackson 
Schultz makes the following observations : " Whether 



UTILISATION OF TANNERS' WASTE. 457 

from green or dry stock, the trimmings should be thrown 
into weak lime as soon as they leave the beam, and should 
be retained in this lime until the hair will almost drop 
off; when in this condition they should be thrown into a 
revolving wheel (tumbler), or may be put into the hide 
mill, and worked until all the hair has been separated 
from the pieces. If a bountiful supply of water has been 
allowed to run on while the wheel or mill was in operation 
all the hair will have worked off and separated from the 
pieces, which will then have parted with so much of their 
lime as to make them, when dry, flinty and hard; to 
avoid- this they should be thrown back into the lime for a 
few days, and again ' raised.' Before they are taken out 
to dry they should be thoroughly washed. The drying 
should be in the open air, and if on a flat board surface 
the pieces should be frequently turned. Care should be 
taken to wash off all the loose lime, so that the pieces 
may present an attractive uniform white and clean sur- 
face. When they are fully dried, they should be pressed 
into uniform bales [cakes]. Under no circumstances 
should any tainted or damaged piece be allowed to go into 
the bale. Paper-makers will use such hide offal for 
sizing, and pay three or four cents per pound more for it 
than glue-makers can afford to pay. Calf skin shanks 
and pates are worth more for this purpose than hide 
cuttings, and should always be kept separate." 

The above observations of a thoroughly practical and 
successful tanner should command attention, and which 
they will doubtless receive, from those who are desirous 
of deriving the full advantage from such valuable offal as 
the trimmings of hides and skins. The cuttings from 
neat cattle are more valuable than those of the sheep, 
while those from goats are of less value than the latter. 

Hair Waste. — Formerly cattle hair was only used by 
plasterers to promote the binding properties of mortar, 
but of late years this material — especially calves' hair — 
has been employed in the manufacture of cloth, carpets, 
and felting. It is of importance, therefore, that this waste 
product should be preserved and rendered saleable by 



4SS LEATHER MANUFACTURE. 

being well cleaned and washed. For this purpose hair 
washing machines have been introduced. 

Lime Waste. — If we bear in mind the very small 
amount of lime which water is capable of dissolving, 
namely, only 88 - 48 grains per gallon at the temperature 
of 60° Fahr., the common practice of putting the cleansed 
skins or hides into what is termed " weak lime," or " old 
lime " — that is to say, lime that has been used over and 
over again — would appear to be open to objection. When 
these old liquors contain little or no caustic lime in solution, 
and chiefly carbonate of lime as the residuum, it is ques- 
tionable whether the cost of labour in handling and loss of 
time involved in what may be an inert process, would not 
be better applied to treating the skins in really active 
(that is, fresh) liquors. The cost of lime is but small, and 
the amount actually exhausted in the process of depilation 
cannot be much. We venture to suggest, therefore, that 
economy would be found, not in trying to get a little more 
out of weak liquors, but in discarding them altogether so 
soon as they give evidence of inaction. Again, the prac- 
tice of using large proportions of lime in charging a pit 
would seem to be objectionable, and for this reason : when 
the lime has fre.ely acted upon the fatty matters of, say, 
100 hides, the liquor becomes a solution of lime-soap, and 
it is doubtful whether in this condition it is capable of 
holding much, if any, free lime in solution. If this be so, 
the liquor would become inoperative as a depilatory, no 
matter how much lime might remain at the bottom of the 
pit. Schultz urges that no undissolved lime should enter 
the pit ; and although we cannot go quite so far as that 
gentleman, we do think that a much smaller proportion of 
lime than is usually adopted would answer every purpose, 
and would be far less wasteful. Our reason for differing 
from the great American authority is, that we believe the 
undissolved lime — which becomes diffused through the 
liquor by the operation of 'plunging each time the skins are 
returned to the pits — has a direct and powerful action 
upon the animal tissues, the epidermis and subcutaneous 
areolar tissue, independent of the dissolved lime, which, aa 



UTILISATION OF TANNERS' WASTE. 459 

we have shown (p. 117), only amounts to 11*6 grains in each 
pint of the liquor at ordinary temperatures. When the 
liquors are highly " soapy/' if we may use the term, the 
action of the lime would be retarded. 

The lime waste of the tanneries is disposed of as manure, 
but the waste liquors are not so easily got rid of, since if 
they are suffered to run into rivers these streams would 
soon become uninhabitable to the finny tribe. A small 
quantity of sulphuric acid, added to the exhausted lime 
liquors, would liberate the fatty acids of the lime-soap, and 
these could be collected as a scum from the surface. If 
this were done exactly to the point of saturation (that is 
to say, without excess of acid), the waste liquor would be 
rendered innocuous, and its entrance into rivers would be 
at all events comparatively harmless. If a small portion 
of lime happened to be present in the waste liquor, this 
would be thrown down as an insoluble sulphate of lime. 

Glucose in Leather. — It has been stated that the 
falsification of the weight of leather, by adding glucose, 
or grape sugar, is carried on somewhat extensively, 
and the shoe trades are seeking protection from this 
system of fraud. The presence of glucose in leather may 
be ascertained in the following way : Steep a piece of 
the suspected leather in a little water for twenty-four 
hours, when the glucose will become dissolved, forming a 
thickish syrupy liquid. Or, if two pieces of the leather 
be moistened and then placed together and left for a time, 
they will be found to adhere firmly, which in the case of 
pure leather would not occur. It is stated that samples of 
sole leather have been found to contain from 30 to 40 per 
cent, of glucose, but this seems incredible. It is a 
peculiarity of leather treated with grape sugar that after 
being wetted it is difficult to dry. 



460 



LEATHER MANUFACTURE. 



French Metrical or Decimal Measures of Length. 



Names. 


Eq. in Metres. 


Equivalents in 


English Inches at 
32° Fabr. 


English Long Measure at 
W Fahr. 


Millimetre . . 
Centimetre . . 
Decimetre .... 

Metre 

Decametre . . 
Hectometre . . 
Kilometre .... 
Myriametre . . 


•001 
•01 

•1 
1- 

ro- 

100- 

1000- 
10000- 


•03937 

•39371 

3-93708 

39-37079 

393-70790 

3937-07900 

39370-79000 

39370790000 


4j h .3 "« "S 

1 3-37 
10 2 9-7 
109 1 1-078 
4 213 1 10-3 
6 1 156 9-17 



*** The standard unit of the above table is the metre, which has been 
determined to be 39-37079 inches at 32" Fahr. (Capt. Kater) ; the Eng- 
lish foot is taken at 62° Fahr. The true length of the metre, reduced to 
the latter temperature, is 39-370091 English inches, a number which 
varies from that in the table only at the fourth decimal figure. It will be 
perceived that the principle of nomenclature adopted in applying the 
names, was to prefix the Greek numerals to the decimal multiples, and the 
Latin numerals to the decimal subdivisions. 



French Metrical or Decimal Measures of Volume. 



Names. 


Eq. in Litres. 


Eq. in English 
Cubic Inches. 


Equivalents in English 
Measures. 








73 










O 


P4 & 


Millilitre 


■001 


•0610 




16-9 


Centilitre .... 


■01 


•6103 




2 49- 


Decilitre 


•1 


6-1028 




3 4 10-36 


Litre 


1- 


61-028 




1 15 1 43-69 


Decalitre 


10- 


610-28 


2 


1 12 1 16-9 


Hectolitre .... 


100- 


6102-8 


22 


1 4 49- 


Kilolitre 


1000- 


61028- 


220 


16 6 40- 


Myrialitre . . 


10000- 


610280- 


2201 


(=275| bushels). 



*** The standard unit in the above table is the litre, or the cube of the 
one-tenth of a metre. The French centiare contains 1 square metre ; the 
are, 100 ditto; the hectare, 10,000 ditto. The old Paris pint is equal to 
1-678 English imperial pint. 

ttt The capacity of solids and aeriform fluids is taken in cubic inches 
or feet, in England.^ In France, the stere, or metre cube, equal to 35-31658 
English cubic feet, is the standard unit. 



WEIGHTS AND MEASURES. 461 

Weights and Measures of the Metrical System. 
From the British Pharmacopoeia. 

Weights. 

1 Milligramme z=z the thousandth part of one gramme, or 0*001 gramme 

1 Centigramme = the hundredth ,, ,, ,, 0-01 

1 Decigramme = the tenth „ ,, ,, 0"1 

1 Gramme ■= weight of a cuhic centimetre of wafer at 4° C. 1*0 

1 Decagramme — ten grammes ..... 10*0 

1 Hectogramme r= one hundred grammes . . . 100 

1 Kilogramme = one thousand grammes . . . 1000-0 (1 kilo.) 

Measures op Capacity. 

1 Millilitre = 1 cubic centimetre, or the measure of 1 gramme of water. 

1 Centilitre = 10 „ ,, ,, 10 „ „ 

1 Decilitre =100 „ „ „ 100 „ 

1 Litre = 1000 „ „ „ 1000 (1 kilo.) 

Measures of Length. 

1 Millimetie = the thousandth part of one metre, or 0-001 metre. 
1 Centimetre = the hundiedth „ „ 0-01 „ 

1 Decimetre = the tenth ,, „ 1 „ 

1 Metre = the ten-millionth part of a quarter of the meridian of 
the earth. 



INDEX. 



A BIES CANADENSIS, 85 
-£*■ Abusive treatment of raw hides, 

53 
Acacia, 83 

arabica, 84 

catechu, 84 

dealbata, 8G 

decurrens, 85 

horrid a, 84 

melanoxylon, 84 

mollissima, 84, 85 

nilotica, 85 

pyeantha, 83 
Acetate of iron, 281 

of lime, 308 
Acetic acid, 17, 301 

fermentation, 142 
Acid, acetic, 17, 301 

carbolic, 66 

catechuic, 75 

catechu-tannic, 14 

chromic, 262, 324 

ellagic, 62, 413 

gallic, 14, 57 

properties of, 58, 60 

gallo-tannic, 43 

hydrochloric, 45, 95, 325 
chromic, 349 

krameric, 80 

malic, 65 

m eta-gal lie, 60 

nitric, 55 

oxalic, 47, 301 

phosphoric, 301 

pyrogallic, 14, 50, 61 

pyroligneous, 65 

quercitannic, 101 

stearic, 312 

sulphuric, 45, 95, 174 
bate, 141 

tannic, 11, 50, 301 

Badviland Lienders' process 
for preparing, 47 



Acid, tannic, Berzelius' process, 44 
Bouillon -Legrange's pro- 
cess, 45 
Coez's process, 47 
Deyeux's process, 46 
Dize's process, 45 
Kohlrausch's process, 48 
Merat-Guillot's process, 45 
Pelouze's process, 43 
Proust's process, 46 
Schering's process, 46 
Serturner's process, 46 
properties of, 49 
pure, 51 
reactions of, 52 
tartaric, 65, 301 

Acids, depilation by, 129 
iron blueing, 14 
greening, 14 

Acroclin, 365 

Action of tannic acid on gelatine, 13 

Adurla, 84 

African gallnut, 87 

Air-heated tumblers, 378 

Albumen, 27 

Alcamo sumach, 78 

Alchemilla vulgaris, 49 

Alcoholic extract of logwood, 304 

Alder, 84 ; bark, 54, 87 

Aldrich's tanning process, 171 

Aleppo nutgalls, 53 
pine, 84 

Algarobiall, 84 

Alkali, caustic, 53 

Alkaline sores, 133 

Alligator skins, 42, 432 

copying by electrotype, 432 

Almardelboom, 84 

Almond oil, 311 

sweet, 311 

Alnus glutinosa, 84 

Alum, 218 

and salt, treatment with, 308 



EREATA IN INDEX. 

Page 462, column 1, line 2, for ' hides ' read ' hide.' 
„ 462, „ 1, „ 3, far < 53 ' read « 35.' 
,, 463, ,, 1, ,, 24,/or' Analysation of catechu ' read' Analysis 

of catechu.' 
,, 463, ,, 1, After I. 24, insert 'Analysis of tannins, 91.' 

,, 464, ,, 1, ,, 52, for ' vegetable ' read ' enamel.' 
,, 464, ,, 1, ,,56, for ' setting for ' read ' setting in.' 
„ 464, „ 2, „ 14, delete ' Blunt tools, 140.' 
,, 465, >> 1) >> 23, for ' fawing ' read ' tawing.' 
„ 465, ., 1, „ 25, for ' for, 348,' read ' for chrome, 348.' 
,, 465, ,, 1, ,, 48, for ' analysation ' read ' analysis.' 
„ 465, ,, 2, „ 19, after ' 91 ' insert ' 104.' 
,, 466, ,, 1, ,, 29, for ' analine ' read ' aniline.' 
„ 468, „ 1, „ 2, for ' 337, 345, 346, 354' read ' 304, 337, 345, 

346, 354.' 
„ 468, „ 1, After 1. 46, insert 'I.A.Ij.T.G. method, 104.' 

,, 468, ,, 2, ,, 21, for ' fellmongering, 434 ' read ' fellmonger- 

ing, 287, 434.' 
,, 468, ,, 2, ,, 24, for ' ascetic ' read ' acetic' 
,, 469, ,, 2, ,, 35, for 'one- and two-bath methods' read 'one- 
bath method.' 
,, 470, „ 2, „ 26, for 'stocking, 400,' read 'stocking, 111,400.' 
,, 471, ,, 1, „ 11, for ' Illustration of the skin, 86,' read 

' Illustration of the skin, 26.' 
,, 472, ,, 2, „ 25, for ' shamoy, 39,' read ' chamois, 39, 357.' 
,, 472, ,, 2, ,, 46, for ' power ' read ' process.' 
„ 474, „ 1, After I. 26, insert ' I.A.L.T.C. method of 

estimating tannin, 104.' 
,, 480, „ 2, ,, 20, for 'Striker ,Priestman's, 407,' read 'Striker, 

Priestman's, 165, 407.' 
„ 481, „ 2, After I. 33, insert ' I.A.L.T.C. method of 

estimating, 104.' 
,, 484, ,, 1, ,, 8, for ' graining in after, 382,' read ' graining 

after, 382.' 



Watt's 'Leather Manufacture.' 



INDEX. 



46; 



Alum dressing, 307, 314, 317 
Alumina,, 47 

chromate of, 175 

sulphate of, 170 
Aluming, 308, 319 
Aluminium chromate, 2G3 
Amber varnish, 298 
Amboyna kino, 75 
American bleaching processes, 270 

method of drying the tanned 
butts, 156 

pearlash, 176 

pendulum roller, 167 

perseverance and ingenuity, 323 

rocker handler, 154, 242 

tanning, 228 

tra^de in leather, 372 

turret drier, 159 

union splitting machine, 322 
Ammonia, 119 

carbonate of, 45, 141 
Ammoniacal salts, 255 
Ammonium, chromate of, 263 
Analysation of catechu, 75 
Anatto, 382 

Aniline colours, dyeing with, 300, 
337, 345, 346, 354 
dyeing with pure, 304 
in glove dyeing, 303 
Animals' skins, classification of, 28 
Anopterus glandulosa, 86 
Antiferments, 151 
Antigalline, 67 
Apricot-bark, 54 
Arabic gum, 340, 439 
Arctium lappa, 49 
Arctostaphilos uva ursi, 84 
Areameter, Connolly's, 430 
Areca catechu, 84 
Areolar tissue, 23, 26 
Argol bath, 175 
Aim-stake, 342 

board, 382 
Arnica montana, 49 
Arok kenema, 84 
Arrasa, 84 

Arsenic limes, depilation by, 329, 330 
Artificial tannin, 55 
Aru mata, 84 
Asacum, 84 
Ash-bark, 54 

ley, 276 

soda. 234 
Ashes, wood, 219, 253 
Ashing, 253 
Asphodel plant, 47 
Asiidospermum quebracho, 77, 86 



Ass and mule hides, 38 
Asses' skins, 439 
Atherospernia moschata, 86 
Avens root, 53 
Avicennia nitida, 84 
Avicennica tormentosa, 86 

BABOOL, 84 
Badvil and Lienders' process for 
preparing tannic acid, 47 
Balsamo, 84 
Ballatschano and Trenk's process, 

174 
Banksia australis, 85 
Baramalli, or pump wood, 84 
Barium, chloride of, 263 
Bark, alder, 54, 87 

apricot, 54 

ash, 54 

beech, 54 

birch, 54 

cinchona, 49 

common willow, 21 

cork-iree, 72 

elm, 54 

examination of, 89 

extract of, 245 

grinding tbe, 237 

harvesting, 72 

hazel, 54 

horse chestnut, 49 

iron, 85 

kermes oak, 85 

larch, 54 

mills, 405 

mimosa, 54, 83 

oak, 21, 68, 143 
tanning, 143 

old oak, 53 

sassafras, 54 

sycamore, 54 

willow, 54 

winter's, 55 

young oak, 53 
Barking of trees, 71 
Barkometer, 90 
Barks, 68 
Barley, 294 

dressing, 294 
Barley-meal, 294 

bating with, 141 
Baron's process of quick tanning, 219 
Basic sulphate of iron, 261 
Basils, 39, 414, 435 

oak-tanned, 435 
Bate or grainer, 139 

sulphuric acid, 141 



464 



INDEX. 



Bath dyeing, 301 

sumac, 388 
Bating, 139, 225, 332 

lactic acid for, 142 

Turnbull's process, 141 

with bailey-mtal, 141 

Warrington's process, 141 
Battery, 48 

Beabejum stellatum, 84 
Beam, 124, 369 

fleshing on the, 283 

house, 124 

knife, French, 236 
German, 236 

unhairing on the, 124 

work, 236 

working on the, 124 
Beamsman or shaver, 375 
Bearberry, 84 

Beck's process of depilation, 136 
Bell Stephens' method of estimating 

tannin, 92 
Bell's process of quick tanning, 

219 
Belt leather, 33 

or crop leather, 226 
Bengal catechu, 53, 75 
Bennet, berb, 17 
Benzine, 263 
Benzol, 454 
Berzelius' process for preparing tannic 

acid, 44 
Betel, 84 
Betula alba, 84 
Betuline, 282 

Bez and Sons' process, 8, 192 
Bichromate of potash, 266 
Birch, 84 

bark, 54 

oil, distillation of, 282 

oil of, 282 

tar oil, 265 
Bisulphide of calcium, depilation by, 

132 
Bitartrate of potash, 175 
Black dye, 300, 339 

for chrome leathers, 339, 340, 
353 

glace manufacture, 327-344 

grain, high shoes, 396 
Kussia leather, 281 

vegetable, 297 
wattle, 84 

wood, 84 
Blackthorn, 54 

Blacking and setting for currying, 
390 



Bleaching leather, 269, 362 

processes, American, 270 
Blocking boot-fronts, 397 

machine, 397 
Blood wood, 84 
Bloom, 413 
Blue dye, 300 

galls, 73 

gum, 84 

Prussian, 297 

Saxon, 300 
Blue-backing, 337, 351 
Blueing, iron tannin, 13 
Blunt tool, 110 
Boa constrictor, 432 
Bohemian olive, 54 
Boiler, tan-burning, 455 
Bombay catechu, 21, 53, 75 
Bombax malebarica, 85 
Bone gelatine, 452 
Boomah, 84 

Boot-fronts, blocking, 97 
Borate of zinc, 264 
Bot, or gadfly, 31 
Bottles, skm, 5 
Bottom sizes, 383, 384 
Bouillon-Legrange's process for pre- 
paring tannic acid, 45 
Bourdon scourer, 155, 413 
Bower, 343 

Box-calf, manufacture of, 348-350 
Brain's process for soitining dried 

hides, 111 
Bran drench, 308, 316 

dressing, 296 

liquor, 296 

steep, 318 
Branding, 31 
Branning, 308 
Brazil wood, 277 
Breakers, 309 
Breaking, 307 
Brined hides, 37 
Brokers, buyers', 373 
Brown soap, 391 
Brysonima, 85 
Bucida buceras, 84 
Buck skin dressing, 366 

tallow, 396 
Buff leather, 38, 363 

machine, 390 

process, 363 
Buffalo hides, 38 
Buffs, polishing, 38 
Burbidge's tanning process, 203 
Burette, 94 
Butea frondosa, 76, 84 



INDEX. 



465 



Buteagum, 53 

kino, 84 

superba, 85 
Butt, 28, 126 

dressing, 388 

kip, setting machine, 380 

tanning, 143 
Butts, tanning for sole leather, 
143 

currying kip, 373 

drying the tanned, 156 

sole, 406 
Buyers' brokers, 373 



p^ESALPINIA, 86 
v^ Toriaria, 84 

Calcei mullei, Roman, 6 
Calcium, oxide of, 117 

bisulphide of, 132 
Calf kid, 311 

drying, 317 
for uppers, 314 

skins for uiemel, 295 
fawing, 317 

one- and two- bath methods 
for, 348 
Calves' skins, 38 
Camata, or camatina, 81 
Camel skin, 440 
Cape lambskins, 435 

sheepskins, 435 
Carapa guianensis, 84 
Carbolic acid, 67, 343 
Carbonate of ammonia, 45 
lead, 45 
lime, 117 
potash, 46 
Carpenters' glue, 456 
Carpnn brevifolium, 84 
Casali's process, 10!) 
Cascara, 84 
Cashew, 74 

Cassia, 49 ; auriculata, 86 
Castanea vesca, 84 
Casuarina quadrivalvis, 86 
Catechine, 75 
Catechu, 17, 84 

acacia, 74 

analysation of, 75 

Bengal, 53, 75 

Bombay, 21, 75 

Indian, 75 

Malabar, 75 

Peru, 53 
Catechu-tannic acid, 14 
Cattchuic acid, 75 

2 



Catgut, 447 

Cattle intestines, preparation of, Con- 
tinental method, 441 
Caustic alkali, 52 
lime, 115 

soda, depilation by, 131 
Celery pine, 84 
Centauria cyanus, 49 
Cevil, 84 

Chamois glove leather, 362 
leather, 39, 357, 361, 363 
imitation, 40 
manufacture, 357-303 
Charcoal, depilation by, 133 

skins, colouring, 362 
Checking or preventing gallic fermen- 
tation, 64 
Chemical methods of estimating tan- 
nin, 91 
tanning, 260 

Heinzerling's process, 262, 
^ 263, 324 

Knapp's processes, 261, 324 
Schultz's process, 324 
Vanderstraaten's process, 

266 
theory of, 11 
Chcnopodium, 440 
Cherry-tree, 84 
Chestnut, 84 

extract, 77 
Spanish, 21 
Chinese nut-galls, 53 
Chloride of barium, 263 

potassium, 191 
sodium, 263 
sulphur, ^265 
tin, 46 
zinc, 264 
Chlorine, 24, 97 
Chromate of alumina, 175 
magnesia, 263 
potash, 262 
soda, 262 
Chromates, soluble, 262 
Chrome leather dyeing, 336, 338, 344- 
347 
history and technique, 323 
manufacture, 323-347 

machinery, 415, 419- 

430 
trade revolutionized 
by, 323, 400 
liquors, 334, 349, 350 
tanning, 334, 349 
Chrome-oxy chloride, 349 
Chroming operations, 334 



II 



466 



INDEX. 



Chrome processes, Heinzerling's, 2(52, 
263 
Schultz's, 324 

process, popularity of, 372 

industr}'', 385 
Chromic acid, 263 

tannage, principle of, 324 
Chrysene, 263 
Cinchona bark, 49 
Cinnamon, 49 
Classification of sheepskins, 435 

skins of animals, 28 
Cleansing and washing hides, 224 

raw hides, 109 
Clearing stone, 369 
Clove, 444 
Cloves, 55 
Coal-tar dyes, 300 
Coccoloba uvifera, 86 
Cochineal, 289 
Cod oil, 378, 383, 384 
Coecum, 444 
Coez's process for preparing tannic 

acid, 47 
Cold sweating, 129 

of hides, 231 
Colophony, 265 
Colouring chamois skins, 362 
Colours, analine, dyeing with, 300, 
337, 345, 346, 354 
in glove dyeing, 303 

pure aniline, dyeing with, 304 
Columbian kino, 76 
Compo, 348 
Composition, 396 

for tanning, 253 

of the skin, 27 
Common willow-bark, 21 
Condition of hides and skins, 28 

of raw hides, 108 
Connolly's areameter, 432 
Continental method of liming, 120 

method of preparing cattle intes- 
tines, 441 

method of preparing glove-lea- 
ther, 313 

successful use of corichrome, 
. 346 
Conveyors, 161, 406 
Copal varaish, 298 
Copperas, 51, 300 
Copper filings, 440 

sulphate of, 264 

vitro] of, 305, 353, 354 
Coppice oak, 70 

Copying crocodile and alligator skins 
by electrotype, 432 



Cordova leather, 288 

Cords, lathe, 444 

Cords for tennis bats, &c, 446 

from sheep intestines, 445 
Coriaria myrtifolii, 79 

ruscifolia, 86 
Corichrome mordants, 346 
Corin, 350 

Corium, or true skin, 23 
Cork-tree, 84 

bark, 72 
Cornus sanguinea, 54 
Cortex, 89 

Corrosive sublimate, 65 
Cost of tanning, Schultz on the, 272 
Cotswold sheepskins, 435 
Count Kartstoff's description of 

Russian leather manufacture, 277 
Couruda, 84 
Cowhides, split, currying, 396 

for brown bags, 396 
Cox's tanning process, 198 
Crab wood, 84 
Cream of lime, 436 
Crepida, Roman, 6 
Crocodile and alligator skins, 431 

copying by electrotype, 432 

and serpent skins, 42 
Crocoxylon excelsum, 86 
Crop leather, 226 
Cross-grained roller, 396 
Crosse's process of tanning bv electri- 
city, 258 
Crust goods, 317 
Crutch stake, 317 
Crystallised verdigris, 439 
Cube gambier, 77 
Curmpuay, 84 
Currying, 368 

calf-skins for mem el, 395 

composition for stuffing. 379. 
380 

kip leathers, 371 

levant leather, 392 

preparation of size for, 383, 384, 
385 

satin or glove shoe leather, 385, 
391 

shop, 369 

split cow-hides, 396 

various leathers, 395 

waxed calf-skins, 395 
Curriers' knife, 317, 370 
Cutch, 74, 81 
Cuticle, 11, 23, 26 
Cutis, 11, 23, 26 

vera, 23, 26 



INDEX. 



467 



Cutting (glue boiling), 450 
Cuyama, 84 
Cynips, 43, 73 

DANISH quick tanning process, 221 
Davy, Sir H., on Segu.n's theorv, 
19 
Davj T , Dr., on the action of lime on 

animal matter, 121 
Davy's method of estimating tannin, 

92 
Dead Sea apples, 73 

vat, 120 
De Bock's tanning process, 196 
Deer skins, 41 

tallow, 396 
De?ras«.337, 379, 352 
Dehairing, 115, 329, 330 
De-liming, 332 
agents, 332 
Dennis's tanolin, 349 
Dentelaria, 84 

Depilation, Beck's process, 13G 
by acids, 129 

arsenic limes, 329, 330 
bisulphide of calcium, 132 
caustic soda, 131 
charcoal, 133 
lime, 115, 329, 330 
machinery, 402 
saccharine matter, 131 
sulphide of sodium, 133, 330 
or unhairing skins and hides, 115 
Palmer's process, 134 
by sweating, 128 
De mood's tanning process, 202 
Determination of tannin by specific 

gravity, 89 
Dextrine, 303 
Deyeux's process of preparing tannic 

acid, 46 
Dialysis, 49 

Dietz's process of quick tanning, 217 
Diospyros glutinosa, 85 
Diplolepsis, 43 
Disintegrators, 405 
Distillation of birch oil, 282 
Divi divi, 54, 82, 84 
Dize's process for preparing tannic 

acid, 45 
Dog-skin gloves, 435 
wood berry, 303 
Donzeri sumach, 79 
Doomboom, 84 

Drake's tanning process, 8, 207 
Drawing off the liquor (glue-boiling), 
450 



Drench, bran, 308, 316 
Drenching, 307, 316, 358 
Dressing, alum, 307, 314, 317 

barlev, 294 

bran, 296 

buck skin, 366 

red, 295 

white, Morfit's remarks on, 
295 
Dressing leather, 410 
Dried hides, 30, 110 

softening, 110 

salted hides, 31 
Drumheads, skins for, 439 
Drum-stuffing, 377, 378 
materials, 378 
tumbler, 375, 377 
Dr. Ure's Views on quick tanning, 

213 
Dry distillation, 282 

salted hides, 112 
Dryinsr, 310, 317 

black, 339 

calf skins, 317 

(glue-boiling), 451 

(gut-dressing), 443 

loft, 157 

oil, 297 

the tanned butts, 156 
Dubbin, 377, 384 

Duplex unhairing and fleshing ma- 
chine, 315 
Dussauce on Seguin's theory, 10 
Dussauce's observations on quick tan- 
ning, 215 
Dust, emery, 387 
Dve, black, 300 

blue, 300 

calf-skins, 353 

goat skins, 339 

green, 300 

olive, 300 

puce, 300 

red, 299 

sulfamine, 345 

violet, 300 

yellow, 300 
Dyeing, 318 

aniline colours in glove, 303 

bath, 301 

chrome leather, 336 

fancy shades, 344 

glove-leather, 303 

kid-leather, 300 

leather, 299 

Morocco leather, 299 

on a flat surface, 302 



458 



INDEX. 



Dyeing, with aniline colours, 300, 
337, 345, 346, 354 
logwood and hemolin, 337 
pure aniline colours, 304 

Dyes, coal-tar, 300 

EAST India kips, 37, 392 
Egging, 309, 318 
Elaeocarpus dentatus, 85 
Elder, 54 
Elderberry, 303 
Electricity, tanning by, 254 

tanning by, Crosse's process, 258 

Gaulard's processes, 255, 256 

Meriten's process, 257 

Ward's process, 254 

Electrotype, copying crocodile and 

alligators' skins, &c, by, 432 

copper rollers, 432 

process, 431 
Elk skins, Indian method of pre- 
paring, 268 
Ellagic acid (bloom), 62, 413 
Elm-bark, 54 
Emblica officinalis, 81 
Embossed leather, 7, 430 
Embossing leather, 393. 430 

machines, 414, 431, 433 
Emery dust, 387 
Emulsion or paste, 309 
Enamelled leather, 293 
English oak, 70 
Eosine, 302 
Epidermis, 18, 23, 89 
Epsom salt-<, 196 
Erodin, 332 
Erythrosine, 303 
Essence of turpentine, 181 
Estimation of tannin, 88 

Bell Stephens' method, 92 

by barkometer, 90 

by chemical methods, 91 

Casali's process, 103 

Davy's method, 92 

determined by specific gravity, 
89 

Hammer's method, 93 

Lovventhal's method, 94 

Mr. Hewitt on Lowenthal's me- 
thod, 97 

Procter on do., 100 

Eamspacker's method, 102 
Eucalyptus globulus, 84 

resinifera, 76, 85 

leucoxylon, 87 
Eugenia, maire, 86 
Examination of bark, 89 



Exocarpus cupressiformus, 84 
Extinction of wax leather, 372 
Extract, chestnut, 77 

hemlock, 77 

Hungarian larch, 77 

larch, 77 

mangrove, 80 

oakwood, 77, 377 

of bark, 245 

quebracho, 77 
Extractive, 18, 213, 222 
Extracts, tanning, 74 

TRAGUS CUNNINGHAMI, 85 
-L Menziesii, 86 

Fat-liquoring chrome leather, 337, 

345, 351 
Fat-liquors, 337, 338, 362, 363 
Feeding of leather, 20, 214 

the skin, 149 
Fellmongered, 287 
Fellmongering, 434 
Fellmongers, 287 
Fells, 287 
Fermentation, ascetic, 142 

acetous, 205 

putrefactive, 128 

putrid, 442 
Ferric acetate, 14 

salts, 14 

sulphate, 14 
Fibrilke, 25 
Fibrm, 17, 18 
Fig bath, 288 
Filandre, 446 
Finishing, 381 

chamois, 361 

glazed kid, 341 

machinery, 406, 423 
First boiling (glue), 449 

English patents for tanning, 169 
Fish, dog, 345 

glue, 446 

oil, 311 

shagreen, 440 

skin, or fish shagreen, 440 
Flaming, 291 
Fleshing, 124 

and unhairing, 283 

by machinery, 315, 331, 404 

knife, 115, 125 

on the beam, 283 
Flesh splits, 289 
Flint hides, 30, 110 
Formic acid for bating, 142 
French beam-knife, 236 

glue, 452 



INDEX. 



469 



French kid gloves, 41 
leather, 310 
tannage, 383 
French metrical or decimal measures 
of length, 460 
metrical or decimal measures of 
volume, 460 
Frizing, 358 
Fronts, boot, 397 

Fryer, Watt, and Holmes's tanning- 
process, 209 
Fucus crispns, 266 
Fuller's earth, 297 
Fulling stocks, 110 
Funcke's tanning process, 197 
Fusarmis compressus, 85 
Fustic %ood, 339 

GALL-NUTS, 43 
Galls, 21, 85 
Aleppo, 53 
blue, 73 
Chinese, 53 
decoction of, 57, 58 
green, 73 
infusion of, 59 
Istrian, 53 
large Mecca, 73 
nut, 73 
tamarisk, 86 
white, 73 
GalliB tinctorum, 43 
Gallic acid, 14, 18, 57 

preparation of, 58 
Dumas' method, 58 
Graham's method, 58 
Liebig's method, 58 
pharmaceutical method, 59 
properties of, 60 
Scheele's method, 58 
fermentation, 63 

prevention of, 64 
Gallo-tannic acid, 43 

tannin, 15 
Gambier, or terra japonica, 53, 77, 85 

and sumac liquor, 377 
Gauh, 85 
Gaulard's processes of tanning by 

electricity, 255, 256 
Gelatine, 11, 91 

action of tannic acid on, 13 
bone, 452 
properties of, 11 
sugar, 12 
Gelatinising (glue -boiling), 450 
Gelatinous tissue, 27 
Geranium maculatum, 77, 85 



German beam-knife, 236 
Geum urbanum, 49 
Glace goatskins, 327 

finishing, 341 

kid, 327 

leather, 310, 318, 323 
Glass hydrometer, 91 
Glazed kid, finishing, 311 
Glazing, 394 

box-calf, 356 

chrome leather, 343 
Glecoma hederacea, 49 
Glossing (glue-boiling), 449 
Glove-leather, 387 

chamois, 362 

Continental method of prepar- 
ing, 313 

dyeing, 303 

hide, 386 
Gloves, dog-skin, 435 

French kid, 41 
Glue-boiling, 449 

carpenter's, 456 

fish, 446 

French, 452 

parchment, 453 

pieces, treatment of, 449 

waste, 452 
Glucose in leather, 459 
Gmelin on the action of tannic acid 

on gelatine, 13 
Goat-skins, 40, 327, 328 

glace, 327-344 

d.veing fancy shades, 314 

one- and two- bath methods for, 
326, 327 

Patna, 328, 419 

Swiss, 40 
Goldbeaters' skin, 444 
Graham's method of preparing gallic 

acid, 58 
Grain leather, 386 

splits, 288 
Graining, 382 

after whitening, 382 

board, hand, 382 
Grape sugar, 458 
Green dye, 300 

galls, 73 

hides, 29 

splitting, 411 

luminere, 304 

oak, 85 

sheepskins, 242 

vitriol, 261, 305 
Greening, tannin, iron, 13 
Grinding the bark, 237 



47o 



INDEX. 



Grounding, 818 

Guest and Court's process, 456 

Uuiot's process of quick tanning, 

221 
Gum arabic, 340, 439 
Gut-dressing, 441 

strings for musical instruments, 
446 



HAIR- WASTE, 457 
Hauler's tanning process, 197 
Hammer's method of estimating tan- 
nin, 93 
Hand-graining board. 382 
press, 433 
reel, 235 
roller, 166 
Handler liquor, 147 
the rocker, 243 
Handlers, 147 
Handling, 148, 242 
Hard leather, tanning process for, 

181 
Harness and upper leather, manu- 
facture of, 223 
leather, 223 
Harvesting bark, 72 
Hazel bark, 54 
Heinzerlmg's chrome processes, 262, 

263, 324 
Hemlock, 54, 85 
extract, 77 

lime rough leather, 272 
sweat sole leather, 272 
tannage, 389 
tanning, 245 

Hibberd's process of, 252 
of New Lebanon, N.J., 249 
Hemolin and logwood, dyeing with, 

337 
Hcmpseed, 218 
Herb bennet, 17 
Hcrse, 437 
Hewitt on ■ Lowenthal's method of 

estimating tannin, 97 
Hibberd's process of hemlock tan- 
ning, 252 
Hide and skin cuttings, 456 
glove, 386 
hook, 119 
ox, 28 

splitting machine, 328, 375 
Hides, 28, 29 

and skins, 27 

depilation of, 115 
condition of, 28 



Hides, ass and mule, 38 
brined, 37 
buffalo, 37 

cold sweating of, 229 
cow, 226 

split, for brown bags, 396 
dried, 30, 110 

Brain's process for soften- 
ing, 111 
salted, 31 
softening, 110 
dry, salted, 112 
Hint, 30, 110 
green or fresh, treatment of, 108 

splitting, 411 
hippopotamus, 38 
horse, 38 

tawed, 38 
imported, 109 
infected, 271 
method of sailing, 109 
native, 30 
ox, 38 

raw, cleansing, 109 
condition of, 108 
stocking, 400 
salted, 30 
Schultz's views on the treatment 

of, 112 
selection of, 223 
treatment of, after sweating, 231 

of, in sweat pits, 230 
walrus, 38 
weight of, 30 
wet salted, 112 
High shoes, black grain, 390 
Hinan, 85 

Hippopotamus hides, 8S 
Hog and pig skins, 41 
plum, 85 
skins, 41 
Holm-tree, 85 
Honeysuckle, 85 
Hops, 218 
Horse, the, 104 
bot, 33 

chestnut bark, 40 
hair, 446 
hides, 38 

tawing, 38 
Housings, 39 
Huldi, 85 _ 
Human skin, 24 
Hungarian larch extract, 77 
Hungary leather, 290 
Hydrate of lime, 117 
Hydraulic press, 377, 453 



INDEX. 



47i 



Hydrochloric acid, 45, 95, 325 

chrome oxide, 849 
Hydrogen, sulphuretted, 46 
Hydrometer, 89 

glass, 91 
Hydrostatic pressure, tanning by. 

206 
Hygrometer, 158 

Mason's, 158 
Hyposulphite of soda, 324 



TLLUSTRATION of the skin, 86 
-L Imitation chamois leather, 40 

kid, 312 
Imitation Morocco leather, 287 

pigskin, 414 
Imported hides, 119 
Indian catechu, 75 
Indigo blue, 95 

carmine, 97 
Induline, 304 

Inflation (gut dressing), 443 
Influence of light on leather, 161 
Infusion of galls, 96 

oak-bark, 96 

sumach, 96 
Instruments, musical, gut strings for, 
446 

stringed, 447 
Intestines, cleansing, 447 

sheep, cords from, 445 

treatment of, 447 
Iris pseudacorus, 49 
Irish, old, process of tanning, 268 
Iron, acetate of, 281 

bark, 85 

basic sulphate of, 261 

blueing acids, 14 
tannin, 13 

oxide salt, 261 

persalts of, 13 

persulphate of, 13 

protosulphate of, 51 

sesquichloride of, 52 

sesquioxide of, 264 

soap, 261 

sulphate of, 264 

tannate of, 51 
Isinglass, 11 
Istrian nut galls, 33 



JAMAICA kino, 75 
*) Japan earth, 77 

leather, 298 
Jennings' tanning process, 174 



KAOLIN, 100 
Kararalli, 85 
Kartstoff's description of Russia lea- 
ther manufacture, 277 
Kassu, 85 

Keasley's tanning process, 182 
Kermes oak, 85 

bark, 53 
Kettledrums, 439 
Kid butt-setting machine, 380 
calf, for uppers, 314 
glazed, finishing, 341 
imitation, 312 
leather, 307 

currying, 371 
dyeing, 300 
French, 300 
skins, 40 

treatment of, 307 
Kino, or gum kino, 49, 76, 85 
Amboyna, 75 
Columbian, 76 
Jamaica, 75 
Kip-skins, 113 

butts, currying, 373 
offal, 386 
Kips, 28, 37, 861, 373 

East India, 37, 392 
Kleman's tanning process, 204 
Knapp's process of chemical tanning, 
261 
chrome process, 324 
Knife, beam, French, 236 
curriers' 317, 370 
fleshing, 125 
moon, 318 
rounding, 127 
shaving:, 371 
unhairing, 124 
Knoppern, 85 

Knowlys and Duesbury's tanning pro- 
cess, 208 
Kohlrausch's process for preparing 

tannic acid, 48 
Krameria triandri.i, 79, 86 
Krameric acid, 80 
Krupelboom, 85 
Kullaballi, 85 

LAMBS' skins, 39 
Lamium album, 49 
Lampblack, 383, 395 
Lange, on the abusive treatment of 

hides, 35 
Larch, 85 

bark, 54 
extract, 77 



472 



IXDEX. 



Large Mecca galls, 73 
Larix americana, 85 

europsea, 85 
Lathe cords, 444 
Laurus sassafras, 80 
Layer liquor, 71 
Layers, the, 149, 243 
Laying the grain, 155 
Leaches, 146 
Leaching, 238 
Lead, carbonate of, 45 
Leather, American trade in, 372 
belt, 38 
bleaching, 269 
buff, 38, 363 

process, 363 
chamois, 39, 357, 361, 363 
colouring, 362 
glove, 362 

manufacture, 357-363 
chrome, manufacture, 323-347 

Schultz's patent, 324 
cloth, American, 267 
Cordovan, 2, 288 
crop or belt, 226 
currying kip, 371 
dressing, 410 

machinery, 410-412 
dyeing, 299 
embossed, 7 
embossing, 431 
enamelled, 297 
extinction of wax, 372 
feeding of, 20, 214 
French kid, 310 
glace, 310 
glove, 387 

Continental method of pre- 
paring, 313 
dyeing, 303 
glucose in, 459 
goat-skin, 327 
grain, 382, 386 

hard, tanning process for, 181 
hemlock tanned, 245 
sweat sole, 272 
Hungary, 290 
imitation chamois, 40 

Morocco, 287 
influence of light upon, 161 
Jamaica, 298 
Japan, 298 
kid, 307 

dyeing, 300 
Levant, 392 
machine-buffed, 390 
Madras, 374 



Leather, manufacture of harness and 
upper, 223 
manufacture, machinery em- 
ployed in, 399-430 
Morocco, 2, 282 
dyeing, 299 
oak lime, 272 
oiled, 394, 435 
ornamental, 42 
ornamenting, 431 
patent, 297 
preservative, 328 
red Morocco, 299 
rolling, 165 
rough, hemlock lime, 272 

oak lime, 272 
Russia, 276 

another method of prepar- 
ing, 279 
black, 281 

manufacture, Count Kart- 
stoff's description of, 
277 
shagrin, 2, 38 
shammy, or shamoy, 39 
sheep, white, 318 
skiver, 288, 322, 356 
smoke-cured, 5 
soaking the, 374 
soft, tanning process for, 181, 

374 
softening the, 374 
tanning butts for sole, 143 
tawed, 317 
to determine when tanned 

throughout, 167 
union lime sole, 272 
vegetable, 265 
vitriol-raised, 241 
Wallachia, 291 
wax, 372, 396 
waxed, 372, 374, 383 
white, manufacture of, 306 
Yuf ts, or Russia, 281 
Leather-making revolutionized by 

chrome power, 323, 400 
Leathers, currying various, 395 
light, manufacture of, 276 
Leaven, 294 
Lecythis ollaria, 85 
Leicester sheepskins, 435 

willow, 21 
Leucine, 12 

Leucospermum conecarpum, 85 
Ley, ash, 276 
Leys, potash, 447 
Liber, 69 



INDEX. 



473 



Liebig's method of preparing gallic 

acid, 58 
Light leathers, manufacture of, 276 
Lignin, 72 
Lignum vita?, 369 
Lime, acetate of, 308 

arsenic, 829, 330 

carbonate of, 117 

caustic, 115 

cream of, 436 

depilation by, 115, 329, 330 

Dr. Davy on the action of, on 
animal matter, 121 

hydrate of, 117 

middle, 315 

milk of, 115, 449 

process, 115 

supposed disadvantages of, 
121 

properties of, 117 

saccharate of, 141 

storing the, 118 

sulphuret of, 132 

tannate of, 16, 71 

waste, 458 
Lime-water, 45 
Limestone, 117 
Liming, 118, 224, 307, 329 

and soaking, 315 

Continental method of, 120 
Lincoln sheepskins, 435 
Linseed oil, 265 
Liquor, bran, 296 

logwood, 385 

oak -bark, 269 
List of tanning materials, 84 
Lithrum salicaria, 49 
Live vat, 120 
Loft or shed, drying, 157 
Logwood and hemolin, d3 - eing with, 

327 
Lomas' tanning process, 176 
Lombardy poplar, 54 
Lowenthal's method of estim- ting 
tannin, 94 

Hewitt on, 97 
Procter on, 100 
Lumiere green, 304 
Lupkin's unhairing process, 233 

MACHINE, hark mills, 404 
blocking, 397 
buffing, 417 
buff leather, 390 
butt-stretching, 425 
depilating and fleshing, 402, 421 
disintegrating, 405 



Machine, embossing, 414, 431-433 
Huxham & Brown's, 431, 
the Altura, 431 
fleshing, 315 
fluffing, 426 
glazing, 427 
kip butt-setting, 380 
measuring, 429, 430 

Connolly's areameter, 430 
printing, 433 
rolling, 166, 409 
scouring, 155, 413 
scudding, 422 
setting, 414 
shaving, 375, 410 
softening, 416 
splitting, 320, 375, 411 
staking, 425, 426 
stocking, 400 
striking, 164, 406 
stuffing, 415 

unhairing and fleshing, 419 
Duplex, 315 
Machinery employed in leather manu- 
facture, 399-430 

embossing, 414, 431-433 
sole leather tanning, 400-419 
unhairing and fleshing by, 315 
used in chrome leatber manu- 
facture, 415, 419-430 
Madder, 219 
Madras leather, 374 
Magnesia, chromate of 262 

tannate of, 71 
Mala insana, 73 
Malabar catechu, 75 
Malic acid, 65 
Manganese, oxide of, 264 

sulphate of, 264 
Mangrove, 85 
Manufacture of box-calf, 348-356 

of chamois, or oil-leather, 357- 

363 
of chrome leather, 323-347 

machinery, 415, 419-430 
of harness and upper leather, 

223 
of leather, machinerv employed 

in, 397 
of light leather, 276 
of white leather, 306 
Marsh rosemary, 85, 86 
Mason's hygrometer, 158 
Materials, drum-stuffing, 378, 380 
Measures and weights of the metrical 
system, 460 

of capacity, 461 



474 



INDEX. 



Measures, of length, 461 

French metrical or decimal, 

460 
volume, French metrical or 
decimal, 460 
Measuring (gut dressing), 443 
Memel, calf -skins for, 395 

roller, 395 
Me'ne, M., 269 
Merat-Guillot's process for preparing 

tannic acid, 45 
Meriten's process of tanning by elec- 
tricity, 258 
Meta-gallic acid, 60 
Methanil yellow, 302 
Method of preparing Russia leather, 
279 

Bell Stephens', for estimating 

tannin, 92 
Continental, of preparing cattle 
intestines, 441 

of preparing glove-leather, 
313 
Davy's, for estimating tannin, 92 
Hammer's, for estimating tan- 
nin, 93 
Indian, of preparing elk-skins, 

268 
Lowenthal's, for estimating tan- 
nin, 94 
of drying the tanned butts, Ame- 
rican, 156 
of estimating tannin, Hewitt on 
Lowenthal's, 97 

Procter on LowenlhalV, 100 
Kampacker's, 102 
of liming, Continental, 120 
of salting hides, 109 
single pit, 118 
Methods of tanning, old, 144 

in up-to-date leather works, 372 
Methyl violet, 304 

Metrical or decimal measures of 
length, French, 460 

of volume, French, 460 
Michel, Kollen, and Hirtzog's pro- 
cess, 176 
Middle lime, 315 
Milk of lime, 115, 449 
Milling, 359, 364, 366 
Mimosa, 85 

bark, 54, 83 
Miscellaneous processes, 268 
Mixed tannages, 151 

vitriol, 305 
Mixture stuffing, 379, 380 
Mochrus, 85 



Modern system of tanning, 145 
Mogadore skins, 40 
Molina sumach, 79 
Molle, 85 

Moon-knife, 318, 342 
Mora, 85 

excelsa, 85 
Mordants, 301, 337 

corichrome, 346 
Morfit's observations on tannin, 55 

remarks on while dressing, 
295 
Moringa pterygosperma, 86 
Morocco leather, 2, 282 

dyeing, 299 

imitation, 38, 287, 414, 432 

red, 299 
Mould, 156 
Mouren's tanning process bv pressure, 

209 
Mr. Ashe's description of the skin, 

24 
Mucilage, 439 
Muriate of tin, 191 
Murici, 85 
Musical instruments, gut strings for, 

446 
Mutton tallow, 440 
Myrobalans, 54, 81, 85, 392, 405 
Myrtle, 85 



NAHRUNG, 313 
Naphthaline, 203 

yellow, 302 
Napktkol yellow, 3U4 
Native hides, 30 
Neb neb, 85 
Nectandra, 86 
Needham's process of quick tanning, 

218 
Nets, sails and cordage, tanning, 

265 
New tanning materials, 86 
Newton's tanning process, 170 
Nigrosine, 304 
Nilrate of soda, 262 
Nitric acid, 55, 261 
Nossiter's tanning process, 198 
Nuessly's process of quick tanning, 

218 
Nut-galls, 15, 73 

Aleppo, 53 

Chinese, 53 

Istrian, 53 
Nutmeg, 444 
Nymphaja alb.i, 49 



INDEX. 



475 



OAK, 85 
bark, 21, 69, 143 

infusion, 98, 278 
tanning with decoction of, 
265 

coppice, 70 

English, 70 

kermes, 53 

lime leather, 272 

rough leather, 272 

tanned basils, 435 

valonia, 81, 405 
Oakwood extract, 77, 377 
Oatmeal, 278 
Observations on the origin of warbles, 

32 
CEstrus bovis, 31, 34 
Offal, 30 

kip, 386 
Oil, almond, 311 

birch-tar, 265 

cod-liver, 378, 383 

cod, 383, 384 

drying, 297 , 

fish, 311 

leather, 357 

linseed, 394 

neatsfoot, 337, 34.0 

of birch, 281 

of sesame, 289 

of vitriol, 241 

rape, 265 

Russian, 281 

sod, 360, 379 

tanning, 357 

thyme, 263 
Oiled leather, 394, 435 

buff leather, 435 

chrome leather, 340 
Old Irish process of tanning, 263 

methods of tanning, 144 

oak bark, 53 
Olca europsea, 85 
Olive, 85 

dye, 300 
On the cost of tanning, 272 
One-bath method for calf-skins, 348 
for goat-skins, 326 
Ooze, 21, 146 

preparation of, 146 
Operation, tawing, 306 

shaving, 375 
Orach, wild, 3 

Orgereau's tanning process, 173 
Ornamental leather, 42, 431 
Ornamenting leather, 431 
Ovipositor, 32 



Oxalic acid, 101, 301 
Ox-bot, 33 

gadfly, 33 
Oxide of calcium, 117 

of iron, salt of, 261 

of manganese, 264 

PAGE'S tanning process, 191 
Palachy, 85 

Palmer's process of depilation, 134 

Paper-making, pulp for, from waste 
tan, 455 

Papyrus, 437 

Paraffin, 265 

Parchment glue, 453 

and vellum, preparation of, 437 
vellum and shagreen, 437 

Parenchyma, 69 

Parnell's views on tannic acid, 50 

Paste, tawing, 313 

Patent leather, 297 

Patents for tanning, first English, 169 

Pates, 231 

Patna goat-skins, 328, 419 

Pearlasb, American, 176 

Pectin, 72 

Pe'louze's process for preparing tannic 
acid, 43 

Pelt, 24 

Pelts, rounding, 126 

Pendulum roller, American, 167 

Pseonia officinalis, 49 

Percentage of tannin in vegetable sub- 
stances, table of, 53 

Pergamena, 437 

Permanganate of potash, 94 

Perones, Roman, 6 

Persalts of iron, 13 

Persian berries, 304 

Persulphate of iron, 13 

Peru catechu, 53 

Pharmaceutical methods of preparing 
gallic acid, 59 

Phloxine, 302 

Phosphoric acid, 301 

Photogen, 263 

Phylanthus emblica, 84 

Phyllocladus asplenifolia, 84 
trichomanoides, 86 

Physiological uses of bark in plants, 
69 

Pickled skins (Australian and New 
Zealand), 327 

Pig and hog skins, 41 

Pigskin, imitation, 414 

Pinus excelepensis, 84 
pinea, 86 



476 



INDEX. 



Pits, sweat, 229 

treatment of hides in, 230 
Plumbigo europaea, 84 
Plum-tree, 54 
Polishing buffs, 38 
Polygonum amphibium, 86 

bistorta, 49 
Pomegranate, 54, 85 
Popularity of chrome process, 372 
Porpoise skins, 42 
Porto sumach, 79 
Potash, bichromate of, 266, 324 
bitartrate of, 175 
carbonate of, 46 
chromate of, 263 
leys, 447 

permanganate of, 94 
prussiate of, 262 
tannate of, 71 
Potassium, chloride of, 191 

tun^state of, 264 
Potentilla argentea, 49 

reptans, 43 
Poterium sanguisorba, 49 
Pratt's system of tinning, 245 
Preliminary operations, 108 
Preparing elk-skins, Indian method, 
268 

gloveleather, Continental method 

of, 313 
the currier's knife, 317, 370 
Preparation of cattle intestines, 441 
of gallic acid from galls, 58 
parchment and vellum, 437 
size for currying, 383-385 
tannic acid, Badvil and Lien- 

ders' process, 47 
tannic acid, Berzelius' process, 

44 
tannic acid, Bouillon -Le- 

grange's process, 45 
tannic acid, MM. Coez's pro- 
cess, 47 
taunic acid, Deyeux's process, 

46_ 
tannic acid, Dize''s process, 

45 
tannic acid, Kohlrausch's pro- 
cess, 48 
tannic acid, Merat-Guillot's 

process, 45 
tannic acid, Pe'louze's process, 

43 
tannic acid, Proust's process, 

46_ 
tannic acid, Schering's pro- 
cess, 46 



Preparation of tannic acid, Ser- 
turner's process, 46 
the blacking for currying, 390 
the ooze, 146 
" Press " leach, 239 

hydraulic, 377, 453 
Priego sumach, 79 
Priestman's striker, 407 
Principles of tanning, 7 
Printing machine, 433 
Process, Badvil and Lienders, for 
preparing tannic acid, 47 
Berzelius', for preparing tannic 

acid, 44 
Bez and Sons', for tawing, 8, 192 
Bouillon-Legrange's, for prepar- 
ing tannic acid, 45 
buff leather, 363 
chrome, Heinzerling's, 262, 263, 
324 
popularity of, 372 
Knapp's, 324 
Schultz's, 324 
Coez's, for preparing tannic acid, 

47 
Crosse's, of tanning bv electri- 
city, 258 
Deyeux's, for preparing tannic 

acid, 46 
Dize's, for preparing tannic acid, 

45 
Drake's tanning, 8, 207 
electrotype, 431 
for softening dried hides, 

Brain's, 111 
Gaulard's, of tinning by electri- 
city, 255, 256 
Guest and Court's, 456 
Hibberd's, of hemlock tanning, 

252 
Keasle}-'s, 8, 182 
Knowlys' and Duesbury's, 8, 208 
Kohlrausch's, for preparing tan- 
nic acid, -48 
lime, 115 

supposed disadvantages of, 
121 
Merat-Guillot's, for preparing 

tannic acid, 45 
Meriten's, of tanning by electri- 
city, 257 
Nossiter's, 8, 198 
of bating, Turnbull's, 141 
bating, Warrington's, 141 
chemical tanning, Vander- 

straaten's, 266 
depilation, Beck's, 136 



INDEX. 



477 



Process of depilation, Palmer's, 134 
tanning, Drake's, 207 
Fryer, Watt and Holmes's, 

209 
Knowlys and Duesbury's, 

208 
Mouren's, 209 
Spilsbury's, 206 
Pelouze's, for preparing tannic 

acid, 43 
Proust's, for preparing tannic 

acid, 46 
quick tanning, 211 

Baron's process, 219 
Bell's process, 219 
Danish process, 221 
Dietz's process, 217 
Guiot's process, 221 
Needham's process, 218 
Nuessly's process, 218 
Schering's, for preparing tannic 

acid, 46 
Serturner's, for preparing tannic 

acid, 46 
Spilsbury's, 8, 206 
tanning, Aldrich's, 171 

Ballatschano and Trenk's, 

174 
Bez and Sons', 192 
Burbidge's, 203 
Cox's, 198 
De Bock's, 196 
Desmond's, 202 
for hard leathers, 181 
for soft leathers, 181 
Funcke's, 197 
Hamer's, 197 
Jennings', 174 
Keasley's, 182 
Kleman's, 204 
Lomas', 176 
Michel, Kollen and Hert- 

zog's, 176 
Newton's, 170 
Nossiter's, 198 
Old Irish, 268 
Orgereau's, 173 
Page's, 191 
Snyder's, 196 
unhairing, Prof. Lupkin's, 

233 
Ward's, of tanniDg by electricity, 
254 
Processes of chemical tanning, 
Knapp's, 261 
Ileinzerling's chrome, 262, 263 
miscellaneous, 268 



Procter on Lowenthal's method of 

estimating tannin, 100 
Properties of gallic acid, 60 

of gelatine, 11 
lime, 117 
tannic acid, 49 
Prosopis pallida, 84 
Protea grandiflora, 86 
Protosulphate of iron, 51 
Proust's process for preparing tannic 

acid, 46 
Pressure, tanning by, 206 
Prussian blue, 297 
Prussiate of potash, 263 
Pterocarpus erinaceus, 76 

marsupium, 76, 85 
Puce dyes, 300 
Pudis sumach, 79 
Pulp for paper-making from waste 

tan, 455 
Punica granatum, 85 
Pure aniline colours, dyeing with, 304 

or drench, 140, 316 

tannic acid, 51 
Purimbas, 85 
Puring, 316, 332 
Putrefactive fermentation, 128 
Putrid fermentation, 442 
Putting out chrome leather, 340 
Pyenocama macrophylla, 84 
Pyrogallic acid, 14, 50, 61 
Pyroligneous acid, 65, 67 

QUEBEACHO, 86 
extract, 77 
Quercitannic acid, 101 
Quercitron, 86 
Quercus coccifera, 70, 85 
fflgilops, 81, 86 
falcata, 70 
glomerata, 70 
ilex, 85 

infectoria, 43, 74, 85 
macrolepis, 81 
pedunculata, 70, 85 
pubescens, 85 
robur, 70 
rubra, 70 
sessiliflora, 70, 85 
stenophylla, 81 
suber, 70, 84 
tinctoria, 70, 86 
Quick tanning, 211 

Baron's process, 219 
Bell's process, 219 
Danish process, 221 
Dietz's process, 217 



478 



INDEX. 



Quick tanning, Dr. Ure's views on, 

213 
Dussauce's observations on, 

215 
Guiot's process, 221 
Needham's process, 218 
Nuessly's process, 218 

KAISING, 138, 292, 297 
or swelling, 131 
Raising with vitriol, 241 
Ramspacker's method of estimating 

tannin, 102 
Rape oil, 205 
Raw hides, abusive treatment of, 35 

]V1. Lange on the abusive treat- 
ment of, 35 
Reactions of tannic acid, 52 

stocking, 400 
Recipes for size, 384, 385 
Red arsenic, 329 

birch, 86 

dressing, 295 

dve, 299 

Morocco leather, 299 
Remarks, Morrit's, on white dressing, 

295 
Reptile skins, 431 
Resin, 263, 379 
Re-tanning, 376, 392 
Rete mucosum, 23 
Rbatany, 68, 86 

root, 53, 80 
Rheum rhaponticum, 49 
Rhus coriaria, 78, 86 

cotinus, 77 

myrtifolia, 85 

semialata, 74 
Roan, 290 
Roans, 435 
Roller, American pendulum, 167 

electrotyped copper, 332 

hand, 165 
Rolling machine, 166, 409 

the leather, 165 
Roman calcei mullei, 6 

crepida, 6 

perones, 6 

shoes, 6 

soleae, 6 

strings, 447 
Rosa canina, 49 

gallica, 49 
Rounding, or trimming, 236, 373 

and sorting, 373 

knife, 127 

table, 126 



Rounding the pelts, 126 

Rubstone, 370 

Russia leather, black, 281 

leather, 2, 277 

method of preparing, 279 

or Yufts, 279 

wormwood, 289 
Rye meal, 294 

QACCHARATE of lime, 141 

£5 Saffron, 86 

Sagre, 3 

Sagri, 3 

Sal ammoniac, 440 

soda, 218 
Salix alba, 86 

cinerea, 86 
Salt, iron, 261 

solution, 191 
Salted hides, 30 

dry, 112 

wet, 112 
Saltpetre, 191 
Salts, ammoniacal, 255 

ferric, 14 
Salvia officinalis, 49 
Salzburg vitriol, 305 
Sam, or samm, 155, 396 
Sandstone, 369 
Sanguisorba officinalis, 49 
Sassafras, 86 

bark, 54 
Saul tree, 86 
Saxon blue, 300 
Scarf skin, 11, 23, 26 
Scheele's method of preparing gallic 

acid, 58 
Schultz on the cost of tanning, 272 

description of the turret drier 
by, 159 
Schultz's chrome leather process, 324 

views on the treatment of hides, 
112 
Scilla maritima, 86 
Scotch stone, 370 
Scouring, 155 

(gut dressing), 441 

house, 368 

machines, 155, 413 

stone, 155 
Scraping, 442 
Scud, 316 
Scudding, 125, 140, 284, 316, 333, 365, 

366 
Seal skin, 297 

skins, 41 
Seaside grape, 86 



INDEX. 



479 



Seasoning, 317, 343, 355, 394 
Seasons ior box-calf, 355 

for chrome leather, 342, 343, 
346 
Sebaceous glands, 26 
Second boiling (glue), 452 
Seguin's theory of the art of fanning, 
15 
Sir H. Davy on, 17 
Dr. Ure on, 16 
Dussnuce on, 16 
Selection of hides, 31, 223 
Sensitive plant, S3 
Serpent and crocodile skins, 42 
Seruirner's process for preparing tan- 
nic acid, 46 
Servic&tree, 55 
Sesame, oil of, 289 
Setting, 380 

kip butt, machine, 380 
Sesquichloride of iron, 52 
Sesquioxide of iron, 264 
Shagreen, 440 

fish. 440 

leather, 2, 38 

parchment and vellum, 437 
Shamois leather, 39 
Shark skin, 440 
Shaver or beamsman, 375 
Shaving, 317, 336, 351 

by machinerv, 375, 410 

knife, 371, 410 

operation, 375 
She oak, 86 
Sheep intestines, cords from, 445 

leather, white, 318 

skins, 39 

classification of, 435 
green, 242 
splitting, 320, 392 
tawing, 318 
Shoe.', high, black grain, 396 

Eoman, 6 
Shop, the currying, 369 
Shorea robusta, 86 
Sicilian sumach, 78 
Silicon, sulphate of, 266 
Single pit method, 118 
Sir John Lubbock on the origin of 

warbles, 32 
Sirnabelli, 86 
Size, recipe for, 384, 385 

preparation of, 384, 453 

for waxed leather, 385 
Sizes, bottom, 383, 384 
Skeleton drum. 235 

reel, 235 



Skin, 23, 26 

and hide cuttings, 456 

bottles, 5 

buck, dressing, 366 

camel, 440 

composition of, 27 

deer, 41 

fish, or fish shagreen, 440 

goldbeaters', 444 

hog, 41 

horse, 440 

human, 24 

illustration of the, 26 

Mr. Ashe's description of the, 

24 
seal, 298 
shark, 440 

structure of the, 23, 36 
wild ass, 440 
Skins 28 

alligator, 42, 431 

&c, electrotyped, 432 
and hides, 28 

condition of, 38 
depilation or unhairing 
of, 115 
asses', 439 
boa-constrictor, 432 
calf, for memel, 395 
tawing, 314, 435 
calves', 38 

chamois, colouring, 362 
crocodile, 432 

elk, Indian method of prepar- 
ing, 268 
for drumheads, 439 
goat, 40, 327, 328, 419 
hog and pig, 41 
kid, 40 

treatment of, 307 
lamb, Cape, 435 
lambs', 435 
Mogadore, 40 
pickled (Australian and New 

Zealand), 327 
porpoise, 42 
reptile, 431 
seal, 41 

serpent and crocodile, 42 
sheep, 39 

Cape, 435 

Cots wold, 435 

classification of, 435 

Leicester, 435 

Lincoln, 435 

Southdown, 435 
smoking, 279 



480 



INDEX-. 



Skins, split, 440 

splitting, 320, 38G, 411 

tawing, 306 

treatment of, 435 

Welsh, 435 
Skiver, 39, 288, 325 

leather, 322, 35G 
Sleaker, 377, 381, 393 

stone, 387 

whitening, 381, 390 
Slimed, 312 
Small steel, 370 
Smoke-cured leather, 5 

house, 128 
Smoking skins, 279 
Snyder's tanning process, 196 
Soaking and liming, 315 

the leather, 374 
Soap, brown, 391 

iron, 261 

soft, 352 
Sod oil, 360, 379 
Soda ash, 234 

caustic, 131 

chromate of, 262 

hyposulphite of, 324 

nitrate of, 262 

sal, 218 

thiosulphite of, 324 
Sodium, sulphide of, 133 

tungstate of, 264 
Soft leather, tanning process for, 

181 
Softening dried hides, 110 
Sogah, 86 
Solea?, Roman, 6 
Sole butts, 456 

leather tanning, machinery used 
in, 400-430 
Soluble chromates, 263 
Sorting and rounding, 373 
Sources of tannin, 68 
Southdown sheepskins, 435 
Spanish chestnut, 21 

white, 180 
Spent tan, 455 

Spilsbury's tanning process, 206 
Split co w -hides, currying, 396 
for brown bags, 396 

flesh, 289 

sheepskins, 440 
Splitting, 39, 387, 388_ 

machine, 320, 375 

sheep-kins, 320 
Spondias lutea, 85 
Squill, 53 
Squills, 86 



Stake, 320 

Staking, 310, 317, 320, 341 

Starching, 382 

Statice, 53, 86 

coriaria, 85, 86 
Steam sweat, 229 
Stearic acid, 312 
Stearine, 263, 312, 379 
Steep, bran, 318 
Still-born calves, 437 
Stocking, 359, 366 
Stocks, fulling, 110 
Stockstone, 377 
Stone pine, 86 

sleaker, 387 
Stoning, 382, 387 
Storing the lime, 118 
Straight-grain roller, 396 
Strasburg vellum, 439 
Striker, Priestman's. 407 
Striking, 163, 308 

a butt, 164 

machine, 164 

pin, 163 
Striking out chrome leather, 336, 340, 

351 
Stringed instruments, 446 
Strings, Roman, 447 
Structure of the skin, 23, 26 
Stryphnodendron barbatemas, 86 
Stuffing machine mixture, 379, 

380 
Subaujuna, 86 
Sugar, gelatine, 12 

grape, 459 
Sulfamine dyes, 345 
Sulphate of alumina, 170 
copper, 264 
iron, basic, 261 
manganese, 264 
protoxide of iron, 264 
silicon, 266 
zinc, 221, 264 _ 
Sulphide of sodium, depilationby, 133, 

330 
Sulphur, 234 

chloride of, 265 
Sulphuration, 443 
Sulphuret of lime, 132 
Sulphuretted hydrogen, 46, 329 
Sulphuric acid, 95, 141, 174, 301, 337, 

388 
Sumach, 86 

and gambier liquor, 377 

bath, 388 

Alcamo, 78 

Donzeri, 79 



INDEX. 



4S1 



Sumach, infusion, 97 

Molina, 79 

Porto, 79 

Portuguese, 79 

Priego, 78 

Silician, 78 

tanning, 285 

Valladolid, 79 
Supposed disadvantages of the lime 

process, 121 
Suspenders, 153 
Suspension, tanning by, 153 
Sweat pits,' 229 

treatment of hides in, 230 

steam, 229 
Sweating, 128 

cjjld, 129, 229 

depilation by, 128 

of hides, cold, 229 

treatment of hides, after, 231 
Sweet liquors, 251 

oil of almonds, 311 
Swelling, or raising, 138 
Swiss goat-skins, 40 
Sycamore bark, 54 

System, metrical, weights and mea- 
sures of the, 461 

modern, of tanning, 145 

TABLE of the percentage of tannin 
in vegetable substances, 53 
Tallow, buck, 396 
deer, 396 
mutton, 440 
Tallowing, 395 
Tamaria gallica, 87 
Tamarisk galls, 86 
Tamarix indica, 86 
Tampico skins, 40 
Tan pits, 152 
shrub, 55 
spent, 454 
Tan-burning boiler, 454 
Tangede, 86 
Tannage, French, 382 

hemlock, 389 
Tannate of iron, 51 

lime, 16, 71 
magnesia, 71 
potash, 71 
tin, 46 
Tanned butts, drying, 156 
Tanners' machinery, 399-430 

waste, utilisation of, 455 
Tannic acid, 11, 43, 50, 301 

preparation of, Badvil and 
Lienders' process, 47 



Tannic acid, preparation of, Berzelius' 
process, 44 
preparation of, Bouillon-Le- 

grange's process, 45 
preparation of, Coez's pro- 
cess, 47 
preparation of, Deyeux's 

process, 46 
preparation of, Dize's pro- 
cess, 45 
preparation of,Kohlrausch's 

process, 48 
preparation of, Merat-Guil- 

lot's process, 45 
preparation of, Pelouze's 

process, 43 
preparation of, Proust's pro- 
cess, 46 
preparation of, Schering's 

process, 46 
preparation of, Serturner's 

process, 46 
properties of, 49 
pure, 51 
reactions of, 52 
Tannin, 11, 18, 43 

Bell Stephens' method of esti- 
mating, 92 
Davy's method of estimating, 92 
Hammer's method of estimating, 

93 
Hewitt on Lowenthal's method 

of estimating, 97 
Lowenthal's method of esti- 
mating, 94 
Procter on Lowenthal's method 

of estimating, 100 
Ramspacker's method of esti- 
mating, 102 
table of percentage of, in vege- 
table substances, 53 
Tanning, 226 

American, 228 

as distinguished from tawing, 

306 
bark, 143 
butts, 143 

for sole leather, 143 
by electricity, 254 

Crosse's process, 258 
Gaulard's process, 255, 256 
Meriten's process, 257 
Ward's process, 254 
by pressure, 206 

Drake's process, 207 
Fryer, Watt, and Holmes's 
process, 209 



2i 



4S2 



INDEX. 



Tanning, by pressure, Knowlys and 
Duesbury's process, 208 

Mouren's process, 209 

Spilsbury's process, 206 
by suspension, 153 
chemical, Knapp's process, 261 
Vanderstraaten's process, 266 
chrome, 334, 349 
composition for, 253 
cost of American, 272 
extracts, 74 

first English patents for, 169 
glycerine in, 269 
Heinzerling's chrome process, 

262, 324 
hemlock, 245 

Hibberd's process, 252 

of New Lebanon, N.J., 249 
materials, 68 
modern system of, 145 
nets, sails, and cordage, 269 
old Irish process of, 268 

methods of, 144 
Pratt's system of, 245 
principles of, 7 
process, Aldrich's, 171 

Ballatschano and Trenk's, 
174 

Bez and Sons', 192 

Burbidge's, 203 

Cox's, 198 

De Bock's, 196 

Dennis's taolin, 349 

Desmond's, 202 

Funcke's, 197 

Guiot's, 221 

Hamer's, 197 

hard leather, 181 

Jennings', 174 

Keasley's, 182 

Kleman's, 204 

Lomas', 176 

Michel, Kollen, and Hert- 
zog's, 176 

Newton's, 170 

Nos>iter's, 198 

Orgereau's, 173 

Page's, 191 

Prenzlau's corin. 350 

Procter's, 350 

Snyder's, 196 

soft leather, 181, 374 
processes, 169 
quick, 211 

Baron's process, 219 

Bell's process, 219 

Danish process, 221 



Tanning, quick, Dietz's process, 
217 
Dr. lire's views on, 213 
Dussauce's observations on, 

215 
Guiot's process, 221 
Needham's process, 218 
Nuessly's process, 218 

Schultz on the cost of, 272 

Seguin's theory of, 15 

sole leather, machinery used in, 
400 

sumach, 285 

theory of, 1 1 
Tanno-gelatine, 51, 91 
Tannometer, 102 
Tanolin, 349 
Taps, or leaches, 146 
Tarsekeha, 86 
Tartar, 299 
Tartaric acid, 65, 301 
Tasmanian laurel, 86 
Tawed hides, 38 

leather, 317 
Tawing, 306, 314, 435 

as distinguished from tanning, 
306 

calf-skins, 314 

operations, 306 

paste, 313 

Schultze's process, 324 

sheepskins, 318 
Tea, 17 

Tennis bats, &c, cords for, 446 
Terce, 86 
Terminalia bellerica, 81 

chelula, 81, 85 

citrina, 85 

formentosa, 87 
Terra japonica, 53, 86 
Thiosulphite of soda, 324 
Third boiling (glue), 452 
Thyme oil, 3 
Tilia Europaea, 49 
Tin, chloride of, 46 

muriate of, 191 

tannate of, 46 
Titration, 94 
To determine when leather is tanned! 

throughout, 167 
Tongs, 283 
Top-sizing, 384 
Tooth-board, 396 
Tormentil, 54, 86 
Tormentilla erecta, 49 
Tormentilia potentilla, 86 
Towhai, 86 



INDEX. 



483 



Trade in American leather, 372 

Tramping drum, 262 

Treatment of glue pieces, 449 

green or fresh hides, 108 
hides after sweating, 231 
hides in sweat pits, 230 
intestines, 447 
kid skins, 307 
skins, 435 

preliminary, 108 
with alum and salt, 308 

Trees, barking of, 71 

Trichinae, 32 

Trichinosis, 32 

Trimming, or rounding, 236, 342, 373 

True skin, 11, 26 

Tuckjng, 362 

Tuga vesca, 86 

Tumbler, 308, 415 
air-heated, 378 

Tungstate of potassium, 264 
of sodium, 264 

Turnbull's process of bating, 141 

Turning over (gut dressing), 442 

Turpentine, essence of, 181 

Turret drier, American, 159 
working of, 160 

Turwar, 86 

Two-bath method for calf-sHns, 348 
for goat-skins, 327 



UNCAFJA GAMBIR, 74, 77, 86 
Unhairing, 124, 315 
Unhairing and fleshing, 315, 329 

by machinery, 315, 402, 429 
by Prof. Lupkin's process, 233 
knife, 124 

or depilation of skins and hides, 
115 
Union lime sole leather, 272 

splitting machine, 322, 412 
Uppers, calf kid for, 314 
Ure on Seguin's theory, 16 
Utilisation of tanners' waste, 455 
Uva ursi, 49 



YALLADOLID sumach, 79 
Valonia, 54, 81, 86, 405 
Valonia oak, 81 
Vanderstraaten's process of chemical 

tanning, '266 
Various leathers, currying, 395 
Varnish, 297 

amber, 298 
copal, 298 



Vegetable black, 297 

extractive, 45, 215 

tannin, 266 

wax, 265 
Vellum and parchment, preparation 
of, 437 

parchment, and shagreen, 437 

Strasburg, 439 
Verdigris crystallised, 439 
Vinegar, 292 

wood, 218' 
Violet dve, 300' 

methyl, 304 
Vitriol, copper, 305 

green, 261, 305 

oil of, 241 

raised leather, 241 

raising with, 241 

Salzburg, 305 

zinc, 305 
Vitriols, mixed, 305 



WAGEN boom, 86 
Wallachia leather, 291 
Walrus hides, 38 
Warble marks, 31 

Warbles, observation on the origin 
of, 32 
Sir John Lubbock on the origin 
of, 32 
Ward's process of tanning by elec- 
tricity, 254 
Warrington's process of bating, 141 
Washing and cleansing, 224, 334, 300, 
365 

(gut dressing), 442 
Waste, glue, 453 
hair, 457 
lime, 132, 458 
tanners', utilisation of, 455 
Water plantain, 86 

stove, 136 
Wax leather, 372, 374, 396 
extinction of, 372 
vegetable, 205 
Waxed leather, 383 
kip butts, 373 
Waxing, 383 
Weights of hides, 30 

and measures of the metrical 
system, 461 
Weinmannia racemosa, 86 
Welsh sheepskins, 435 

stone, 370 
Wet salted hides, 112 
Whip cords, 446 



4 8 4 



INDEX. 



White dressing, 130 

Mornt's remarks on, 295 

galls, 73 

leather, manufacture of, 30G 

mangrove, 85 

sheep leather, 318 
Whitening, 381, 382 

graining in after, 382 

sleaker, 381, 390 
Wild ass skin, 440 

orach, 3 
Willow, 86 

hark, 54 

Leicester, 21 
Wilson's striker, 407 
Winter's bar' - , 55 
Woo-pei-tzee, 74 
Wood ashes, 219 
Woolstapler, 287, 436 



Working in rounds, 118 

of the turret drier, 159 
on the beam, 124 

Works, methods in up-to-date leather, 
372 

Wormwood, Russia, 289 

YEAST, 296 
- 1 - Yellow dye, 300 
Yellow methanil, 302 

naphthol, 304 

naphtholine, 302 
Young oak-bark, 53 
Yufts Russia leather, 279 

ZINC, borate of, 264 
chloride of, 264 
sulphate of, 264 
vitriol, 350 



THE END 



FttlNTKD tit WILLIAM CLOWES AND SONS, LIMITED, LONDON AND BECCLES. 



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Moment of Inertia. — Centre of Oscillation. — Electricity. — Strength 
of Materials. — Elasticity. — Test Sheets of Metals. — Friction. — 
Transmission of Power. — Flow of Liquids. — Flow of Gases. — Air 
Pumps, Surface Condensers, &c. — Speed of Steamships. — Propellers. — 
Cutting Tools. — Flanges. — Copper Sheets and Tubes. — Screws, Nuts, 
Bolt Heads, &c. — Various Recipes and Miscellaneous Matter. — With 
DIAGRAMS for Valve-gear, Belting and Ropes, Discharge and Suc- 
tion Pipes^ Screw Propellers, and Copper Pipes. 

Part II : Treating of Power of Boilers. — Useful Ratios — Notes 
on Construction. — Cylindrical Boiler Shells. — Circular Furnaces. 
Flat Plates. — Stays. — Girders. — Screws. — Hydraulic Tests. — Rivet- 
ing. — Boiler Setting, Chimneys, and Mountings. — Fuels, &c. — Exam- 
ples of Boilers and Speeds of Steamships. — Nominal and Normal 
Horse Power. — With DIAGRAMS for all Boiler Calculations and 
Drawings of many Varieties of Boilers. 

THE WORKS' MANAGER'S HANDBOOK. 

Comprising Modern Rules, Tables, and Data. For Engineers, Mill- 
wrights, and Boiler Makers ; Tool Makers, Machinists, and Metal 
Workers; Iron and Brass Founders, etc. By W. S. Hutton, Civil 
and Mechanical Engineer, Author of "The Practical Engineer's Hand- 
book." Sixth Edition, carefully Revised and Enlarged. 8vo, strongly 

bound $6.00 

t2^~ The Author having compiled Rules and Data for his own use in a great 
variety of modern engineering work, and having found his notes extremely use- 
ful, decided to publish them — revised to date — believing that a practical work, 
suited to the daily requirements of modern engineers, would be favorably 
received. 
1 "The Author treats every subject from the point of view of one who has 
collected workshop notes for application in workshop practice, rather than 
from the theoretical or literary aspect. The volume contains a great deal 
of that kind of information which is gained only by practical experience 
and is seldom written in books." — The Engineer. 

STEAM BOILER CONSTRUCTION. 

A Practical Handbook for Engineers, Boiler-makers, and Steam Users. 
Containing a large Collection of Rules and Data relating to Recent Prac- 
tice in the Design, Construction, and Working of all Kinds of Stationary, 
Locomotive, and Marine Steam-boilers. By Walter S. Hutton, 
Civil and Mechanical Engineer, Author of "The Works' Manager's 
Handbook," "The Practical Engineer's Handbook," &c. With up- 
wards of 500 Illustrations. Fourth Edition, carefully Revised and 

ErJarged. 8vo, over 680 pages, cloth, strongly bound $6.09 

t5F".ihis Work is issued in continuation of the series of handbooks 
written 6y the Author, viz: "The Works' Manager's Handbook" and 
"The Practical Engineer's Handbook," which are so highly appreciated 
by engineers for the practical nature of their information, and is consequently 
written in the same style as those works. 

Contents: — Heat, Radiation, and Conduction, Non-conductin g 
Materials, and Coverings for Steam Boilers. — Composition, Calorific 
Power, and Evaporative Power of Fuels. — Combustion, Firing Steam 
Boilers, Products of Combustion, &c. — Chimneys for Steam Boilers. — 



4 CROSBY LOCKWOOD &■ SON'S CATALOGUE. 

Steam Blast. 1 — FORCE Draught."— FEED Water. — Effect of Heat on 
Water. — Expansion of Water by Heat. — Weight of Water at Differ- 
ent Temperatures. — Convection. — Circulation. — Evaporation. — 
Properties of Saturated Steam. — Evaporative Power of Boilers. — 
Priming, &c. — Water-Heating Surfaces of Steam Boilers. — Trans- 
mission of Heat. — Smoke Tubes. — Evaporative Powers and Effi- 
ciency of Boilers. — Water Capacity and Steam Capacity of Boilers. — 
Fire-Grates, Fire-Bridges, and Fire-Bars. — Power of Boilers. — 
Cylindrical Shells and Furnace-Tubes of Boilers, &c. 

Tests of Materials. — Strength and Weight of Boiler-Plates. — 
Effect of Temperature on Metals. — Rivet Holes. — Rivets. — Rivet 
Joints of Steam Boilers. — Caulking. — Ends of Cylindrical Shells. — 
Stays for Boilers, &c. — Steam Generators. — Description and Pro- 
portions of Cornish, Lancashire, and Other Types of Stationary 
Boilers. — Boiler Setting. — Multitubular Boilers. — Locomotive 
Boilers. — Portable Boilers. — Marine Boilers. — Vertical Boilers. — 
Water-tube Boilers. — Superheaters. — Cost of Steam Production. — 
Furnaces for Refuse Fuels. — Destructors, &c. 

Safety- Valves. — Steam Pipes. — Stop- Valves, and Other Mountings 
for Boilers. — Feed Pumps. — Steam Pumps. — Feed- Water Consumption. 
— Injectors. — Incrustation and Corrosion. — Feed- Water Heaters. — 
Evaporators. — Testing Boilers. — Evaporative Performances of 
Steam Boilers. Steam-Boiler Explosions, &c. 

PLATING AND BOILER MAKING. 

A Practical Handbook for Workshop Operations. By Joseph G. Hor- 
ner, A.M.I.M.E. 380 pp. with 338 Illustrations. 12mo cloth. .$3.00 
Contents: — The Trade. — Tools. — Materials. — Testing Materials. — 
Limiting Dimensions and Weights of Materials. — Cutting and 
Straightening Plates, &c. — Bending Plates. — Bending Angles, &c. — 
Welding. — Flanging. — Punching. — Riveting. — Types of Riveted 
Joints. — Estimation of Lengths of Material. — The Marking Out of 
Work. — The Estimation of Weights, &c. — Machines. 

A TREATISE ON STEAM BOILERS. 

Their Strength, Construction, and Economical Working. By R. Wil- 
son, C.E. Fifth Edition. 12mo, cloth $2.50 

"The best treatise that has ever been published on steam boilers." — En- 
gineer. 

BOILER AND FACTORY CHIMNEYS. 

Their Draught-Power and Stability. With a chapter on Lightning Con- 
ductors. By Robert Wilson, A.I.C.E., Author of "A Treatise on 
Steam Boilers," etc. 12mo, cloth $1.50 

BOILERMAKER'S ASSISTANT 

In Drawing, Templating, and Calculating Boiler Work, etc. By J. 
Courtney, Practical Boilermaker. Edited by D. K. Clark, C.E. 
Seventh Edition. 12mo, cloth .80 

BOILERMAKER'S READY RECKONER. 

With Examples of Practical Geometry and Templating for the Use of 
Platers, Smiths, and Riveters. By John Courtney. Edited by D. 
K. Clark, M.Inst. C.E. Crown 8vo, cloth $1.60 

BOILERMAKER'S READY RECKONER & ASSISTANT. 

With Examples of Practical Geometry and Templating for the Use of 
Platers, Smiths, and Riveters. By John Courtney. Edited by D.K. 
Clark, M.Inst.C.E. Fifth Edition, 480 pp., with 140 Illustrations. 
Fcap. 8vo, half-bound $3.00 

*** This Work consists of the two previous-mentioned volumes, "Boiler- 
maker's Assistant" and "Boilermaker's Ready Reckoner," bound 
together in One Volume. 



MECHANICAL ENGINEERING, 6-c. 5 

STEAM BOILERS. 

Their Construction and Management. By R. Armstrong, C.E. Illus- 
trated. Crown 8vo, cloth yQ 

THE PRACTICAL ENGINEER'S HANDBOOK. 

Comprising a Treatise on Modern Engines and Boilers; Marine, Loco- 
motive, and Stationary. And containing a large collection of Rules and 
Practical Data relating to Recent Practice in Designing and Construct- 
ing all kinds of Engines, Boilers, and other Engineering Work. The 
whole constituting a comprehensive Key to the Board of Trade and 
otcer Examinations for Certificates of Competency in Modern Mechan- 
ical Engineering. By Walter S. Hutton, Civil and Mechanical En- 
gineer, Author of "The Works' Manager's Handbook for Engineers," 
&c. With upwards of 420 Illustrations. Sixth edition, Revised and 

Enlarged. Medium 8vo, nearly 560 pp., strongly oound $7.00 

C3F™ This Work is designed as a companion to the Author's "Works' 
Manager's Handbook." It possesses many new and original features, and 
contains, like its predecessor, a quantity of matter not originally intended for 
publication, but collected by the Author for his own use in the construction of a 
great variety of Modern Engineering Work. 

The information is given in a condensed and concise form, and is illus- 
trated by upwards of 420 Engravings; and comprises a quantity of tabulated 
matter of great value to all engaged in designing, constructing, or estimating for 
Engines, Boilers, and other Engineering Work. 

TEXT-BOOK ON THE STEAM ENGINE. 

With a Supplement on Gas Engines and Part II. on Heat Engines 
By T. M. Goodeve, M.A., Barrister-at-Law, Professor of Mechanics at 
the Royal College of Science, London; Author of "The Principles of 
Mechanics," "The Elements of Mechanism," &c. Fourteenth Edition. 

Crown 8vo, cloth $2.0i) 

"Professor Goodeve has given us a treatise on the steam engine which will 

bear comparison with anything written by Huxley or Maxwell, and we can 

award it no higher praise." — Engineer. 

A HANDBOOK ON THE STEAM ENGINE. 

With especial Reference to Small and Medium-sized Engines. For the 
Use of Engine Makers, Mechanical Draughtsmen, Engineering Students, 
and users of Steam Power. By Herman Haeder, C.E. Translated 
from the German, with additions and alterations, by H. H. P. Powles, 
A.M.I.C.E., M.I.M.E. Third Edition, Revised. With nearly 1,100 

Illustrations. 12mo, cloth $3.00 

Summary of Contents : — Introduction. — Types of Steam Engines. — 
Details of Steam Engines. — Governors. — Valve Gears. — Condensers, 

alr-pumps, and feed-pumps. examples of engines of continental 

Make, from Actual Practice. — Particulars of Engines by English 
Makers. — Compound Engines. — Indicator and Indicator Diagrams. — 
Calculations for Power and Steam Consumption. — Effect of Inertia 
on Reciprocating Parts of Engines. — Friction Brake Dynamometer — 
Sundry Details. — Boilers. — Index. 

" There can be no question as to its value. We cordially commend it 
to all concerned in the design and construction of the steam engine." — 
Mechanical World. 

THE PORTABLE ENGINE. 

A Practical Manual on its Construction and Management, for the use 
of Owners and Users of Steam Engines generally. By William Dyson 

Wansbrough. 12mo, cloth $1.50 

"This is a work of value to those who use steam machinery. . . . Should 

be read by every one who has a steam engine, on a farm or elsewhere." — 

Mark Lane Express. 



6 CROSBY LOCKWOOD &• SON'S CATALOGUE. 
THE STEAM ENGINE. 

A Treatise on the Mathematical Theory of, with Rules and Examples 
tor Practical Men. By T. Baker, (J.E. 12mo, cloth 60 

"Teems with scientific information with reference to the steam-engine." — 
Design and Work. 

THE STEAM ENGINE. 

For the use of Beginners. By Dr. Lahdner. 12mo, cloth. . . .60 

LOCOMOTIVE ENGINE DRIVING. 

A Practical Manual for Engineers in Charge of Locomotive Engines. 
By Michael Reynolds, M.S.E. Twelfth Edition. 12mo, cloth 

boards $2.00 

"We can confidently recommend the book, not only to the practical driver, 

but to every one who takes an interest in the performance of locomotive 

engines." — The Engineer. 

THE LOCOMOTIVE ENGINE. 

The Autobiography of an Old Locomotive Engine. By Robert 
Weatherburn, M.I.M.E. With Illustrations and Per traits of George 
and Robert Stephenson. 12mo, cloth $1.00 

THE LOCOMOTIVE ENGINE AND ITS DEVELOPMENT. 

A Popular Treatise on the Gradual Improvements made in Railway 
Engines between 1803 and 1903. By Clement E. Stretton, C.E. 

Sixth Edition, Revised and Enlarged. 12mo, cloth $2.00 

"Students of railway history and all who are interested in the evolution 

of the modern locomotive will find much to attract and entertain in this 

volume." — The Times. 

THE MODEL LOCOMOTIVE ENGINEER, 

Fireman, and Engine-Boy. Comprising a Historical Notice of the 
Pioneer Locomotive Engines and their Inventors. By Michael Reyn- 
olds. Second Edition, with Revised Appendix. 12mo, cloth. $2.00 
"We should be glad to see this book in the possession of every one in the 

kingdom who has ever laid, or is to lay, hands on a locomotive engine." — 

Iron. 

LOCOMOTIVE ENGINES, 

A Rudimentary Treatise on. By G. D. Dempsey, C.E. With large 
Additions treating of the Modern Locomotive, by D. K. Clark, 

M.Inst.C.E. With Illustrations. 12mo, cloth $.120 

"A model of what an elementary technical book should be." — Academy. 

CONTINUOUS RAILWAY BRAKES. 

A Practical Treatise on the several Systems in Use in the United King- 
dom; their Construction and Performance. By M. Reynolds. 8vo, 
cloth $3.50 

ENGINE-DRIVING LIFE. 

Stirring Adventures and Incidents in the Lives of Locomotive Engine- 
Drivers. By Michael Reynolds. Third Edition. 12mo, cloth. .60 

STATIONARY ENGINE DRIVING. 

A Practical Manual for Engineers in Charge of Stationary Engines. By 
Michael Reynolds, M.S.E. Seventh Edition. 12mo, cloth boards. 

$2.00 
THE CARE AND MANAGEMENT OF STATIONARY 

ENGINES. 

A Practical Handbook for Men-in-charge. By C. Hurst. 12mo. .50 



MECHANICAL ENGINEERING, &c. 7 

THE ENGINEMAN'S POCKET COMPANION 

and Practical Educator for Enginemen, Boiler Attendants, and Me- 
chanics. By Michael Reynolds. With 45 Illustrations and numer- 
ous Diagrams. Fifth Edition. Royal 18mo, strongly bound for 

Pocket wear $1.50 

"A most meritorious work, giving in a succinct and practical form all the 

information an engine-minder, desirous of mastering the scientific principles 

of his daily calling, would require." — The Miller. 

THE SAFE USE OF STEAM. 

Containing Rules for Unprofessional Steam Users. By an Engineer. 

Eighth Edition. Sewed .25 

"If steam-users would but learn this little book by heart, boiler explo- 
sions would become sensations by their rarity." — English Mechanic. 

STEAM AND MACHINERY MANAGEMENT. 

A Guide to the Arrangement and Economical Management of Machin- 
ery, with Hints on Construction and Selection. By M. Powis Bale, 
M.Inst.M.E. 12mo, cloth $1.00 

GAS AND OIL ENGINE MANAGEMENT. 

A Practical Guide for Users and Attendants, being Notes on Selection, 
Construction, and Management. By M. Powis Bale, M.Inst.C.E., 
M.I.Mech.E. Author of "Woodworking Machinery," &c. 12mo, 
cloth $1.50 

ON GAS ENGINES. 

With Appendix describing a Recent Engine with Tube Igniter. By 
T. M. Goodeve, M.A. 12mo, cloth $1.00 

THE ENGINEER'S YEAR=BOOK FOR 1906. 

Comprising Formula, Rules, Tables, Data, and Memoranda in Civil, 
Mechanical, Electrical, Marine, and Mine Engineering. By H. R. 
Kempe, M.Inst.C.E., Principal Staff Engineer, Engineer-in-Chief's 
Office, General Post Office, London; Author of "A Handbook of Elec- 
trical Testing," "The Electrical Engineer's Pocket-Book," &c. With 
1,000 Illustrations, specially Engraved for the Work. 12mo, 950 pp., 
leather $3.00 

THE MECHANICAL ENGINEER'S POCKET=BOOK. 

Comprising Tables, Formulae, Rules, and Data: a Handy Book of Ref- 
erence for Daily Use in Engineering Practice. By D. Kinnear Clark, 
M.Inst.C.E., Fifth Edition, thoroughly Revised and Enlarged. By H. H. 
P. Powles, A.M.Inst.C.E., M.I.M.E. Small 8vo, 700 pp., leather. $3.00 
Summary of Contents: — Mathematical Tables. — Measurement of 
Surfaces and Solids. — English Weights and Measures. — French 
Metric Weights and Measures. — Foreign Weights and Measures. — 
Moneys. — Specific Gravity, Weight, and Volume. — Manufactured 
Metals. — Steel Pipes. — Bolts and Nuts. — Sundry Articles in Wrought 
and Cast Iron, Copper, Brass, Lead, Tin, Zinc. — Strength of Mater- 
ials. — Strength of Timber. — Strength of Cast Iron. — Strength of 
Wrought Iron. — Strength of Steel. — Tensile Strength of Copper, 
Lead, &c. — Resistance of Stones and other Building Materials. — 
Riveted Joints in Boiler Plates. — Boiler Shells. — Wire Ropes and 
Hemp Ropes — Chains and Chain Cables. — Framing. — Hardness of 
Metals, Alloys, and Stones. — Labour of Animals. — Mechanical Prin- 
ciples. — Gravity and Fall of Bodies. — Accelerating and Retarding 
Forces. — Mill Gearing, Shafting, &c. — Transmission of Motive Power. 
— Heat. — Combustion. — Fuels. — Warming, Ventilation, Cooking 
Stoves. — Steam. — Steam Engines and Boilers. — Railways. — Tram- 
ways. — Steam Ships. — Pumping Steam Engines and Pumps. — Coal Gas, 
Gas Engines, &c. — Air in Motion. — Compressed Air. — Hot- Air Engines. 
— Water Power. — Speed of Cutting Tools. — Colours. — Electrical 
Engineering. 



8 CROSBY LOCKWOOD &* SON'S CATALOGUE. 

PRACTICAL MECHANICS' WORKSHOP COMPANION. 

Comprising a great Variety of the most useful Rules and Formulae in 
Mechanical Science, with numerous Tables of Practical Data and Cal- 
culated Results for Facilitating Mechanical Operations. By William 
Templeton, Author of "The Engineer's Practical Assistant," &c, &c. 
Eighteenth Edition, Revised, Modernised, and considerably Enlarged, 
by W. S. Hutton, C.E., Author of "The Works' Manager's Hand- 
book," &c. Feap. 8vo, nearly 500 pp., with 8 Plates and upwards of 
250 Diagrams, leather $2.50 

ENGINEER'S AND MILLWRIGHT'S ASSISTANT. 

A Collection of Useful Tables, Rules, and Data. By William Temple- 
ton. Eighth Edition, with Additions. 18mo, cloth $1.00 

TABLES AND MEMORANDA FOR ENGINEERS, 
MECHANICS, ARCHITECTS, BUILDERS, &c. 

Selected and Arranged by Francis Smith. Seventh Edition, Revised, 
including Electrical Tables, Formulae, and Memoranda. Waist- 
coat-pocket size, limp leather > gQ 

THE MECHANICAL ENGINEER'S COMPANION. 

Of Areas, Circumferences, Decimal Equivalents, in inches and feet, mil- 
limetres, squares, cubes, roots, &c. ; Strength of Bolts, Weight of Iron, 
&c. ; Weights, Measures, and other Data. Also Practical Rules for 
Engine Proportions. By R. Edwards, M.Inst.C.E. Fcap. 8vo, cloth. 

$1 00 
MECHANICAL ENGINEERING TERMS. 

(Lockwood's Dictionary of). Embracing those current in the Drawing 
Office, Pattern Shop, Foundry, Fitting, Turning, Smiths', and Boiler 
Shops, &c. Comprising upwards of 6,000 Definitions. Edited by J. 
G. Horner, A.M.I.M.E. Third Edition, Revised, with Additions. 
12mo, cloth $3.00 

"Just the sort of handy dictionary required by the various trades engaged 
in mechanical engineering. The practical engineering pupil will find the 
book of great value in his studies, and every foreman engineer and mechanic 
should have a copy." 

POCKET GLOSSARY OF TECHNICAL TERMS. 

English-French, French-English; with Tables suitable for the Archi- 
tectural, Engineering, Manufacturing, and Nautical Professions. By 
John James Fletcher. Fourth Edition, 200 pp. Waistcoat-pocket 
size, limp leather m QQ 

IRON AND STEEL. 

A Work for the Forge Foundry, Factory, and Office. Containing ready, 
useful, and trustworthy Information for Ironmasters and their Stock- 
takers; Managers of Bar, Rail, Plate, and Sheet Rolling Mills; Iron and 
Metal Founders; Iron, Ship, and Bridge Builders; Mechanical, Mining, 
and Consulting Engineers; Architects, Contractors, Builders, &c. By 
Charles Hoare, Author of "The Slide Rule," &c. Ninth Edition. 
32mo, leather $2.50 

WORKMAN'S MANUAL OF ENGINEERING DRAWING. 

By John Maxton, Instructor in Engineering Drawing, Royal Naval 
College, Greenwich. Eighth Edition. 300 Plates and Diagrams. 

12mo, cloth $1.40 

"A copy of it should be kept for reference in every drawing office." — En- 
gineering. 

PATTERN MAKING. 

Embracing the Main Types of Engineering Construction, and including 
Gearing, Engine Work, Sheaves and Pulleys, Pipes and Columns, Screws, 
Machine Parts, Pumps and Cocks, the Moulding of Patterns in Loam 
and Greensand, Weight of Castings, &c. By J. G. Horner, A.M.I.M.E. 
Third Edition, Enlarged. With 486 Illustrations. 12mo,cloth. $3 00 



MECHANICAL ENGINEERING, &c. 9 

SMITHY AND FORGE. 

Including the Farrier's Art and Coach Smithing. By W. J. E. Crane. 

12mo, cloth $1.00 

"The first modern English book on the subject. Great pains have been 
bestowed by the author upon the book; shoeing-smiths will find it both 
useful and interesting." 

TOOTHED GEARING. 

A Practical Handbook for Offices and Workshops. By J. Horner, 
A.M.I.M.E. Second Edition, with a new Chapter on Recent Practice. 
With 184 Illustrations. 12mo, cloth $2.25 

MODERN WORKSHOP PRACTICE, 

As applied to Marine, Land, and Locomotive Engines, Floating Docks, 
Dredging Machines, Bridges, Shipbuilding, &c. By J. G. Winton. 
Fourth Edition, Illustrated. 12mo, cloth $1.40 

DETAILS OF MACHINERY. 

Compriiing Instructions for the Execution of various Works in Iron in 
the Fitting Shop, Foundry, and Boiler Yard. By Francis Campin, 
CE. 12mo, cloth $1.20 

ENGINEERING ESTIMATES, COSTS, AND ACCOUNTS. 

A Guide to Commercial Engineering. With numerous examples of Es- 
timates and Costs of Millwright Work, Miscellaneous Productions, 
Steam Engines and Steam Boilers ; and a Section on the Preparation 
of Costs Accounts. By A General Manager. Second Edition. 8vo, 
cloth $4.50 

MECHANICAL ENGINEERING. 

Comprising Metallurgy, Moulding, Casting, Forging, Tools, Workshop 
Machinery, Mechanical Manipulation, Manufacture of the Steam En- 
gine, &c. By Francis Campin, CE. Third Edition. 12mo, cloth 

$1.00 

LATHE=WORK. 

A Practical Treatise on the Tools. Appliances, and Processes employed in 
the Art of Turning. By Paul N. Hasluck. Eighth Edition. 12mo, 

cloth $2.00 

"Written by a man who knows not only how work ought to be done, but 

who also knows how to do it, and how to convey his knowledge to others." — 

Engineering. 

SCREW=TH READS, 

And Methods of Producing Them. With numerous Tables and com- 
plete Directions for using Screw-cutting Lathes. By Paul N. Hasluck. 
Author of "Lathe-work," &c. Sixth Edition. Waistcoat-pocket size. 

.60 
"Full of useful information, hints and practical criticism. Tans, dies, 
and screwing tools generally are illustrated and their action described." 

CONDENSED MECHANICS. 

A Selection of Formula 1 , Rules, Tables, and Data for the Use of Engi- 
neering Students, &c. By W. G.C. Hughes, A.M.I.C.E. 12mo, cloth. 

$1.00 

MECHANICS OF AIR MACHINERY. 

By Dr. J. Weisbach and Prof. G. Herrmann. Authorized Translation 
with an Appendix on American Practice by A. Trowbridge, Ph.B., 
Adjunct Professor of Mechanical Engineering, Columbia University. 
Royal 8vo, cloth. Net $3.75 



io CROSBY LOCKWOOD &■ SON'S CATALOGUE. 
PRACTICAL MECHANISM. 

And Machine Tools. By T. Baker, C.E. With Remarks on Tools and 
Machinery by J. Nasmyth, C.E. 12mo, cloth $1.00 

MECHANICS. 

Being a concise Exposition of the General Principles of Mechanical 
Science and their Applications. By C. Tomlinson, F.R.S. 12mo, 
cloth 60 

FUELS: SOLID, LIQUID, AND GASEOUS. 

Their Analysis and Valuation. For the use of Chemists and Engineers. 
By H. J. Phillips, F.C.S., formerly Analytical and Consulting Chemist 
to the Great Eastern Railway. Fourth Edition. 12mo, cloth.. .80 
"Ought to have its place in the laboratory of every metallurgical estab- 
lishment and wherever fuel is used on a large scale." — Chemical News. 

FUEL, ITS COMBUSTION AND ECONOMY. 

Consisting of an Abridgment of "A Treatise on the Combustion of Coal 

and the Prevention of Smoke." By C. W. Williams, A. Inst. C.E. 

With extensive Additions by D. Kinnbar Clark, M.Inst. C.E. 

Fourth Edition. 12mo, cloth $1.50 

"Students should buy the book and read it, as one of the most complete 
and satisfactory treatises on the combustion and economy of fuel to be 
had." — Engineer. 

STEAM AND THE STEAM ENGINE, 

Stationary and Portable. Being an Extension of the Treatise on the 
Steam Engine of Mr. J. Sewbll. By D. K. Clark, C.E. Fourth Edi- 
tion. 12mo, cloth $1.40 

"Every essential part of the subject is treated of competently, and in a 
popular style." 

PUMPS AND PUMPING. 

A Handbook for Pump Users. Being Notes on Selection, Construction, 
and Management. By M. Powis Bale, M.Inst. C.E. , M.I.Mech.E. 

Fourth Edition. 12mo, cloth $1.50 

" Thoroughly practical and clearly written." 

REFRIGERATION, COLD STORAGE, & ICE=MAKING. 

A Practical Treatise on the Art and Science of Refrigeration. By. A. 
J. Wallis-Tatler, A.M. Inst. C.E. , Author of "Refrigerating and Ice- 
Making Machinerv." 600 pp., with 360 Illustrations. Medium 8vo, 

cloth $4.50 

Contents: — Chapter I. Introduction. — II. The Theory and Prac- 
tice op Refrigeration. — III. The Liquefaction Process. — IV. The 
Vacuum Process. — V. The Compression Process or System. — VI. The 
Compression Process (Continued). — VII. The Compression Process (Con- 
tinued). — VIII. Condensers and Water-Cooling and Saving Apparatus. 
— IX. The Absorption and Binary Absorption Process or System. — 
X. The Cold-Air System. — XI. Cocks, Valves and Pipe-Joints and 
Unions. — XII. Refrigeration and Cold Storage. — XIII. Refrigera- 
tion and Cold Storage (Continued). — XIV. Refrigeration and Cold 
Storage (Continued). — XV. Refrigeration and Cold Storage (Con- 
tinued). — XVI. Marine Refrigeration. — XVII. Manufacturing, In- 
dustrial and Constructional Applications. — XVIII. Ice-Making. — 

XIX. The Management and Testing of Refrigerating Machinery. — 

XX. Cost of Working. — XXI. The Production of Very Low Temper- 
atures. — XXII. Useful Tables and Memoranda. — Appendix. — Bibli- 
ography of Refrigeration. 



CIVIL ENGINEERING, SURVEYING, &c. n 

THE POCKET BOOK OF REFRIGERATION AND ICE- 
MAKING. 

By A. J. Wallis-Tayler, A.M. Inst. C.E. Author of "Refrigerating 
and Ice-making Machinery," &c. Third Edition, Enlarged. 12mo 
cloth $1.50 

REFRIGERATING & ICE=MAKING MACHINERY. 

A Descriptive Treatise for the Use of Persons Employing Refrigerating 
and Ice-making Installations, and others. By A. X Wallis-Tayler, 

A.M.Inst.C.E. Third Edition, Enlarged. 12mo, cloth $3.00 

"May be recommended as a useful description of the machinery, the proc- 
esses, and of the acts, figures, and tabulated physics of refrigerating." — En- 
gineer. 

MOTOR VEHICLES FOR BUSINESS PURPOSES. 

A Practical Handbook for those interested in the Transport of Passen- 
gers and Goods. By A. J. Wallis-Tayler, A.M.Inst.C.E. With 134 
Illustrations. Demy 8vo, cloth [Just published.] $3.50 

MOTOR CARS OR POWER=CARRIAGES FOR COMMON 
ROADS. 

By A. i. Wallis-Tayler, A.M.Inst.C.E. 212 pp., with 76 Illustrations. 
12mo, cloth $2.00 

AERIAL NAVIGATION. 

A Practical Handbook on the Construction of Dirigible Balloons, Aero- 
stats, Aeroplanes, and Aeromotors. By Frederick Walker, C.E., 
Associate Member of the Aeronautic Institute. With 104 Illustrations. 
Large 12mo, cloth $3.00 

STONE=WORKING MACHINERY. 

A Manual dealing with the Rapid and Economical Conversion of Stone. 
With Hints on the Arrangement and Management of Stone Works. By 
M. Powis Bale, M.Inst.C.E., M.I.Mech.E. Second Edition, enlarged. 

12mo, cloth $3.50 

"The book should be in the hands of every mason or student of stone- 
work." 

"A handbook for all who manipulate stone for building or ornamental 
purposes." 

FIRES, FIRE=ENGINES, AND FIRE BRIGADES. 

With a History of Fire-Engines, their Construction, Use, and Manage- 
ment; Foreign Fire Systems; Hints on Fire-Brigades, &c. By C. F. 
T. Young, C.E. 8vo, cloth $8.00 

CRANES. 

The Construction of, and other Machinery for Raising Heavy Bodies 
for the Erection of Buildings, &c. By J. Glynn, F.R.S. 12mo, cloth. 

.60 



CIVIL ENGINEERING, SURVEYING, ETC. 
PIONEER IRRIGATION. 

A Manual of Information for Farmers in the Colonies. By E. O. Maw- 
son, M.Inst.C.E., Executive Engineer, Public Works Department, 
Bombay. With Additional Chapters on Light Railways by E. R. 
Calthrop, M.Inst.C.E., M.I.M.E. Illustrated by numerous Plates 

and Diagrams. Demy 8vo, cloth $4.00 

Summary of Contents : — Value of Irrigation, and Sources of Water 
Supply. — Dams and Weirs. — Canals. — Underground Water. — Meth- 
ods of Irrigation. — Sewage Irrigation. — Imperial Automatic Sluice 
Gates. — The Cultivation of Irrigated Crops, Vegetables, and Fruit 
Trees. — Light Railways for Heavy Traffic. — Useful Memoranda and 
Data. 



12 CROSBY LOCKwfiOD &• SON'S CATALOGUE. 
THE RECLAMATION OF LAND FROM TIDAL WATERS. 

A Handbook for Engineers, Landed Proprietors, and others interested 
in Works of Reclamation. By A. Beazely, M.Inst.C.E. 8vo, cloth. 

$4.00 
"The book shows in a concise way what has to be done in reclaiming land 
from the sea, and the best way of doing it. Contains a great deal of prac- 
tical and useful information which cannot fail to be of service to engineers 
entrusted with the enclosure of salt marshes, and to landowners intending 
to reclaim land from the sea." — The Engineer. 

THE WATER SUPPLY OF TOWNS AND THE C0N= 
STRUCTION OF WATER-WORKS. 

A Practical Treatise for the Use of Engineers and Students of Engineer- 
ing. By W. K. Burton, A.M. Inst. C.E., Consulting Engineer to the 
Tokyo Water- works. Second Edition, Revised and Extended. With 
numerous Plates and Illustrations. Super-royal 8vo, buckram. §9.00 
I. Introductory. — II. Different Qualities of Water. — III. Quan- 
tity of Water to be Provided. — IV. On Ascertaining whether a Pro- 
posed Source of Supply is Sufficient. — V. On Estimating the Storage 
Capacity Required to be Provided. — VI. Classification of Water- 
works. — VII. Impounding Reservoirs. — VIII. Earthwork Dams. — IX. 
Masonry Dams. — X. The Purification of Water. — XL Settling Res- 
ervoirs. — XII. Sand Filtration. — XIII. Purification of Water by 
Action of Iron, Softening of Water by Action of Lime, Natural 
Filtration. — XIV. Service or Clean Water Reservoirs — Water 
Towers — Stand Pipes. — XV. The Connection of Settling Reservoirs, 
Filter Beds and Service Reservoirs. — XVI. Pumping Machinery. — 

XVII. Flow of Water in Conduits — Pipes and Open Channels. — 

XVIII. Distribution Systems. — XIX. Special Provisions for the Ex- 
tinction of Fire. — XX. Pipes for Water-works. — XXI. Prevention 
of Waste of Water. — XXII. Various Appliances used in Connection 
with Water-works. 

Appendix I. By Prof. JOHN MILNE, F.R.S. — Considerations Con- 
cerning the Probable Effects of Earthquakes on Water- works, and 
the Special Precautions to be Taken in Earthquake Countries. 

Appendix II. By JOHN DE RIJKE, C.E.— On Sand Dunes and Dune 
Sand as a Source of Water Supply. 

THE WATER SUPPLY OF CITIES AND TOWNS. 

By William Humber, A. M.Inst.C.E., and M.Inst.M.E., Author of 
"Cast and Wrought Iron Bridge Construction," &c, &c. Illustrated 
with 50 Double Plates, 1 Single Plate, Coloured Frontispiece, and up- 
wards of 250 Woodcuts, and containing 400 pp. of Text. Imp. 4to, 

elegantly and substantially half-bound in morocco $45.00 

List of Contents: — I. Historical Sketch of some of the means that 
have been adopted for the Supply of Water to Cities and Towns. — ■ 
II. Water and the Foreign Matter usually associated with it. — III. 
Rainfall and Evaporation. — IV. Springs and the Water-bearing 
Formations of Various Districts. — V. Measurement and Estimation 
of the Flow of Water. — VI. On the Selection of the Source of Sup- 
ply. — VII. Wells. — VIII. Reservoirs. — IX. The Purification of 
Water. — X Pumps. — XL Pumping Machinery. — XII. Conduits. — 
XIII. Distribution of Water. — XIV. Meters, Service Pipes, and 
House Fittings. — XV. The Law and Economy of Water-works. — XVI. 
Constant and Intermittent Supply. — XVII. Description of Plates. — 
Appendices, giving Tables of Rates of Supply, Velocities, &c, &c, 
together with Specifications of Several Works Illustrated, among 
which will be found: Aberdeen, Bideford, Canterbury, Dundee, 
Halifax, Lambeth, Rotherham, Dublin, and others. 

RURAL WATER SUPPLY. 

A Practical Handbook on the Sunnlv of Water and Construction of 
Water-works for small Countrv Districts. Bv Allan Greenwell, 
A.M.Inst.C.E., and W. T. Curry, A.M.Inst.C.E., F.G.S. With Illus- 
trations. Second Edition, Revised. 12mo, cloth $2.00 



CIVIL ENGINEERING, SURVEYING, &°c. 13 

WATER ENGINEERING. 

A Practical Treatise on the Measurement, Storage, Conveyance, and 
Utilization of Water for the Supply of Towns, for Mill Power, and for 
other Purposes. By Charles Slagg, A. M.Inst. C.E. Second Edition. 
12mo, cloth $3.00 

WATER WORKS, FOR THE SUPPLY OF CITIES AND 
TOWNS. 

With a Description of the Principal Geological Formations of England 
as influencing Supplies of Water. By Samuel Hughes. 12mo cloth 

$1.60 
POWER OF WATER. 

As applied to drive Flour Mills, and to give motion to Turbines, and 
other Hydrostatic Engines. By Joseph Glynn, F.R.S., &c. New 
Edition. Illustrated. 12mo, cloth < gQ 

WELLS AND WELL=SINKING. 

By J. G. Swindell, A.R.I.B.A., and G. R. Burnell, C.E. Revised 

Edition. 12mo, cloth ^§q 

"Solid practical information, written in a concise and lucid style. The 
work can be recommended." 

HYDRAULIC POWER ENGINEERING. 

A Practical Manual on the Concentration and Transmission of Power 
by Hydraulic Machinery. By G. Croydon Marks, A. M.Inst. C.E. 
Second Edition, Enlarged, with about 240 Illustrations. 8vo, cloth. 

[Just Published. $3.50 
Summary op Contents: — Principles of Hydraulics. — The Flow op 
Water. — Hydraulic Pressures. — Material. — Test Load. — Packings 
for Sliding Surfaces. — Pipe Joints. — Controlling Valves. — Platform 
Lifts. — Workshop and Foundry Cranes. — Warehouse and Dock 
Cranes. — Hydraulic Accumulators. — Presses for Baling and other 
Purposes. — Sheet Metal Working and Forging Machinery. — Hy- 
draulic Riveters. — Hand and Power Pumps. — Steam Pumps. — Tur- 
bines. — Impulse Turbines. — Reaction Turbines. — Design of Tur- 
bines in Detail. — Water Wheels.— Hydraulic Engines. — Recent 
Achievements. — Pressure of Water. — Action of Pumps, &c. 

HYDRAULIC MANUAL. 

Consisting of Working Tables and Explanatory Text. Intended as a 
Guide in Hydraulic Calculations and Field Operations. By Lowis 
D'A. Jackson, Author of "Aid to Survey Practice," "Modern Metrol- 
ogy," &c. Fourth Edition, Enlarged. 8vo, cloth $8.00 

"The author has constructed a manual which may be accepted as a trust- 
worthy guide to this branch of the engineer's profession." — Engineering. 

HYDRAULIC TABLES, CO=EFFICIENTS, & FORMUL/E. 

For Finding the Discharge of Water from Orifices, Notches, Weirs, 
Pipes, and Rivers. With New Formulae, Tables, and General Informa- 
tion on Rain-fall, Catchment-Basins, Drainage, Sewerage, Water Sup- 
ply for Towns and Mill Power. By John Neville, C.E. , M.R.I. A- 
Third Edition, revised, with additions. Numerous Illustrations. 

12mo, cloth $5.00 

"It is, of all English books on the subject, the one nearest to complete- 
ness." 

MASONRY DAMS FROM INCEPTION TO COMPLETION. 

Including numerous Formulae, Forms of Specifications and Tender, 
Pocket Diagram of Forces, &c. For the use of Civil and Mining En- 
gineers. By C. F. Courtney, M.Inst. C.E. 8vo, cloth $3.50 

"Contains a good deal of valuable data. Many useful suggestions will be 

found in the remarks on site and position, location of dam, foundations 

and constuction." — Building News. 



i 4 CROSBY LOCKWOOD & SON'S CATALOGUE. 
RIVER BARS. 

The Causes of their Formation, and their Treatment by "Induced Tidal 
Scour"; with a Description of the Success! ui Reduction by this Method 
of the Bar at Dublin. By I. J. Manx, Assist. Erig. to the Dublin Port 

and Docks Board. Royal 8vo, cloth $3.00 

"We recommend all interested in harbour works — and, indeed, those con- 
cerned in the improvements of rivers generally — to read Mr. Mann's inter- 
esting work." — Engineer. 



DRAINAGE OF LANDS, TOWNS, AND BUILDINGS. 

By G. D. Dempsey, C.E. Revised, with large Additions on Recent 
Practice in Drainage Engineering by D. Kinnear Clark, M.Inst.C.E. 
Fourth Edition. 12mo, cloth $1.80 

SURVEYING AS PRACTISED BY CIVIL ENGINEERS 
AND SURVEYORS. 

Including the Setting-out of Works for Construction and Surveys 
Abroad, with many Examples taken from Actual Practice. A Hand- 
book for use in the Field and the Office, intended also as a Text-book 
for Students. By John Whitelaw, Jun., A. M.Inst.C.E., Author of 
"Points and Crossings." With about 260 Illustrations. I>emy 8vo, 
doth $4.00 

PRACTICAL SURVEYING. 

A Text-book for Students preparing for Examination or for Survey- 
work in the Colonies. By George W. Usill, A.M. Inst. C.E. Eighth 
Edition, thoroughly Revised and Enlarged, by Aiex Beazeley, 
M.Inst.C.E. With 4 Lithographic Plates and 360 Illustrations. 12mo, 
cloth $3.00 

SURVEYING WITH THE TACHEOMETER. 

A practical Manual for the use of Civil and Military Engineers and Sur- 
veyors, including two series of Tables specially computed for the Re- 
duction of Readings in Sexagesimal and in Centesimal Degrees. By 
Neil Kennedy, M.Inst.C.E. With Diagrams and Plates. Second 

Edition. 8vo, cloth $4.00 

"The work is very clearly written, and should remove all difficulties in the 
way of any surveyor desirous of making use of this useful and rapid instru- 
ment . ' ' — Nature. 

LAND AND ENGINEERING SURVEYING. 

For Students and Practical Use. Py T. Baker, C.E. Twentieth Edi- 
tion, by F. E. Dixon, A.M. Inst. C.E. With Plates and Diagrams. 
12mo, cloth 80 

AID TO SURVEY PRACTICE. 

For Reference in Surveying, Levelling, and Setting-out; and in Route 
Surveys of Travellers by Land and Sea. With Tables, Illustrations, 
and Records. By L. D'A. Jackson, A. M.Inst. C.E. Second Edition. 
8vo, cloth $5.00 

LAND AND MARINE SURVEYING. 

In Reference to the Preparation of Plans for Roads and Railways; 
Canals, Rivers, Towns' Water Supplies; Docks and Harbours. With 
Description and Use of Surveying Instruments. By W. Davis Haskoll, 
C.E. Second Edition, Revised with Additions. Crown 8vo, cloth. 

$3.50 



CIVIL ENGINEERING, SURVEYING, &c. 15 

ENGINEER'S & MINING SURVEYOR'S FIELD BOOK. 

Consisting of a Series of Tables, with Rules, Explanations of Systems 
and use of Theodolite for Traverse Surveying and plotting the work 
with minute accuracy by means of Straight Edge and Set Square only; 
Levelling with the Theodolite, Setting-out Curves with and without the 
Theodolite, Earthwork Tables, &c. By W. Davis Haskoll, C.E. With 
numerous Woodcuts. Fifth Edition, Enlarged. ]2mo, cloth. $4.50 
"The book is very handy; the separate tables of sines and tangents to 

every minute will make it useful for many other purposes, the genuine 

traverse tables existing all the same." 

AN OUTLINE OF THE METHOD OF CONDUCTING 
A TRIGONOMETRICAL SURVEY. 

For the Formation of Geographical and Topographical Maps and Plans, 
Military Reconnaissance, LEVELLING, &c, with Useful Problems, 
Formulae, and Tables. By Lieut. -General Fromb, R.E. I'ourth Edi- 
tion, Revised and partly Re-written by Major-General Sir Charles 
Warren, G.C.M.G., R.E. With 19 Plates and 115 Woodcuts. 8vo, 
cloth $6.0O 

PRINCIPLES AND PRACTICE OF LEVELLING. 

Showing its Application to Purposes of Railway and Civil Engineering 
in the Construction of Roads; with Mr. Telford's Rules for the same. 
By Frederick W. Simms, M.Inst. C.E. Eighth Edition, with Law's 
Practical Examples for Setting-out Railway Curves, and Trautwine's 
Field Practice of Laying out Circular Curves. With 7 Plates and nu- 
merous Woodcuts. 8vo $2.50 

"The text-book on levelling in most of our engineering schools and col- 
leges." — Engineer. 

"The publishers have rendered a substantial service to the profession, 
especially to the younger members, by bringing out the present edition of 
Mr. Simm's useful work." — Engineering. 

TABLES OF TANGENTIAL ANGLES AND MULTIPLES. 

For Setting-out Curves from 5 to 200 Radius. By A. BsAzELEY.M.Inst. 
C.E. 7th Edition, Revised. With an Appendix on the use of the 
Tables for Measuring up Curves. Printed on 50 Cards, and sold in a 

cloth box, waistcoat-pocket size $1.50 

"Each table is printed on a small card, which, placed on the theodolite, 
leaves the hands free to manipulate the instrument — no small advantage 
as regards the rapidity of work." 

"Very handy; aman may know that all his day's work must fall on two 
of these cards, which he puts into his own card-case, and leaves the rest 
behind." 

PIONEER ENGINEERING. 

A treatise on the Engineering Operations connected with the Settle- 
ment of Waste Lands in New Countries. By E. Dobson, M.Inst. C.E. 

Second Edition. 12mo, cloth $1.80 

"Mr. Dobson is familiar with the difficulties which have to be overcome 

in this class of work, and much of his advice will be valuable to young 

engineers proceeding to our colonies." — Engineering. 

TUNNELLING. 

A Practical Treatise. By Charles Prelini, C.E. With additions by 
Charles S. Hill, C.E. With 150 Diagrams and Illustrations. Royal 
8vo, cloth $3.00 

PRACTICAL TUNNELLING. 

Explaining in detail Setting-out the Works, Shaft-sinking, and Heading- 
driving, Ranging the Lines and Levelling underground, Sub-Excavat- 
ing, Timbering and the Construction of the Brickwork of Tunnels. By 
F. W. Simivo, M.Inst.C.E. Fourth Edition. Revised and Further Ex- 
tended, including the most recent (1895) Examples of Sub-aqueous and 
other Tunnels, bv D. Kinnear Clark, M.Inst.C.E With 34 Folding 
Plates. Imperial 8vo, cloth $9.00 



16 CROSBY LOCKWOOD &• S02VS CATALOGUE. 
EARTH AND ROCK EXCAVATION. 

A Practical Treatise, by Charles Prelini, C.E. 365 pp., with Tables, 
many Diagrams and Engravings. Royal 8vo, cloth. 

[Just Published. $3.00 

CONSTRUCTION OF ROADS AND STREETS. 

By H. Law, C.E., and D. K. Clark, C.E. Sixth Edition, revised, with 
Additional Chapters by A. J. Wallis-Tayler, A.M.Inst.C.E. 12mo, 
cloth $2.50 

TRAMWAYS: THEIR CONSTRUCTION AND WORKING. 

Embracing a Comprehensive History of the System ; with an exhaustive 
Analysis of the Various Modes of Traction, including Horse Power, 
Steam, Cable Traction, Electric Traction, <fec; a Description of the 
Varieties of Rolling Stock ; and ample Details of Cost and Working 
Expenses. New Edition, Thoroughly Revised, and Including the 
Progress recently made in Tramway Construction, <fec, &c. By D. 
Kinnear Clark, M.Inst.C.E. With 400 Illustrations. 8vo, 780 pp., 
buckram $7.50 

HANDY GENERAL EARTH=WORK TABLES. 

Giving the Contents in Cubic Yards of Centre and Slopes of Cuttings 
and Embankments from 3 inches to 80 feet in Depth or Height, for use 
with either 66 feet Chain or 100 feet Chain. By J. H. Watson Buck, 
M.In3t.C.E. On a sheet mounted in cloth case $1.50 

EARTHWORK TABLES. 

Showing the Contents in Cubic Yards of Embankments. Cuttings, &c, 
of Heights or Depths up to an average of 80 f eet. By Joseph Broad- 
bent, C.E., and Francis Campin, C.E. 12mo, cloth $2.00 

"The way in which accuracy is attained, by a simple division of each cross 

section into three elements, two in which are constant and one variable, is 

ingenious." 

A MANUAL ON EARTHWORK. 

By Alex. J. Graham, C.E. With numerous Diagrams. Second Edi- 
tion. 18mo, cloth $1.00 

THE CONSTRUCTION OF LARGE TUNNEL SHAFTS. 

A Practical and Theoretical Essay. By J. H. Watson Buck, M.Inst. 
C.E., Resident Engineer, L. and N. W. R. With Folding Plates, 8vo, 

cloth $4.80 

"Many of the methods given are of extreme practical value to the mason, 
and the observations on the form of arch, the rules for ordering the stone, 
and the construction of the templates, will be found of considerable use." 

ESSAY ON OBLIQUE BRIDGES 

(Practical and Theoretical.) With 13 large Plates. By the late George 
Watson Buck, M.Inst.C.E Fourth Edition, revised by his Son, J. H. 
Watson Buck, M.Inst C.E ; and with the addition of Description to 
Diagrams for Facilitating the Construction of Oblique Bridges, by W. 
H. Barlow, M.Inst.C.E Royal 8vo, cloth $4.80 

CAST & WROUGHT IRON BRIDGE CONSTRUCTION 

(A Complete and Practical Treatise on), including Iron Foundations 
In Three Parts. — Theoretical, Practical, and Descriptive By Wil- 
liam Humber, A.M.Inst.C.E , and M.Inst.M.E. Third Edition, revised 
and much improved, with 115 Double Plates (20 of which now first 
appear in this edition ), and numerous Additions to the Text In 2 vols., 
imp. 4to, half-bound in morocco $50.00 

IRON BRIDGES OF MODERATE SPAN: 

Their Construction and Erection By H. W. Pendred With 40 Il- 
lustrations. 12mo, cloth # §Q 



CIVIL ENGINEERING, SURVEYING, &c. 17 

IRON AND STEEL BRIDGES AND VIADUCTS. 

A Practical Treatise upon their Construction. For the use of Engi- 
neers, Draughtsmen, and Students. By Francis Campin, C.E. 12mo, 
cloth $1.40 

TUBULAR AND OTHER IRON GIRDER BRIDGES, 

Describing the Britannia and Conway Tubular Bridges. With a 
Sketch of Iron Bridges, &c. By G. D. Dempsey, C.E. 12mo, cloth, 

.80 

GRAPHIC AND ANALYTIC STATICS. 

In Their Practical Application to the Treatment of Stresses in Roofs, 
Solid Girders, Lattice, Bowstring, and Suspension Bridges, Braced 
Iron Arches and Piers, and other Frameworks. By R. Hudson 
Graham, C.E. Containing Diagrams and Plates to Scale. With num- 
erous Examples, many taken from existing Structures. Specially 
arranged for Class-work in Colleges and Universities. Second Edition, 
Revised and Enlarged. 8vo, cloth $6.00 

WEIGHTS OF WROUGHT IRON & STEEL GIRDERS. 

A Graphic Table for Facilitating the Computation of the Weights of 
Wrought Iron and Steel Girders, &c, for Parliamentary and other 
Estimates. By J. H. Watson Buck, M.Inst.C.E. On a sheet. $1.00 

GEOMETRY FOR TECHNICAL STUDENTS. 

An Introduction to Pure and Applied Geometry and the Mensuration 
of Surfaces and Solids, including Problems in Plane Geometry useful in 
Drawing. By E. H. Sprague, A.M.Inst.C.E. 12mo, cloth. . . .50 

PRACTICAL GEOMETRY. 

For the Architect, Engineer, and Mechanic. Giving Rules for the Delin- 
eation and Application of various Geometrical Lines, Figures, and 

Curves. By E. W. Tarn, M.A., Architect. 8vo, cloth $3.50 

"No book with the same objects in view has ever been published in which 

the clearness of the rules laid down and the illustrative diagrams have been 

so satisfactory." — Scotsman. 

THE GEOMETRY OF COMPASSES. 

Or, Problems Resolved by the mere Description of Circles and the Use 
of Coloured Diagrams and Symbols. By Oliver Byrne. Coloured 
Plates. 12mo, cloth $1.50 

MENSURATION AND MEASURING. 

With the Mensuration and Levelling of Land for the purposes of Modern 
Engineering. By T. Baker, C.E. New Edition by E. Nugent, C.E. 
12mo, cloth .60 

HANDY BOOK FOR THE CALCULATION OF STRAINS 

In Girders and Similar Structures and their Strength. Consisting of 
Formulae and Corresponding Diagrams, with numerous details for Prac- 
tical Application, &c. By William Humber, A.M.Inst.C.E., &c. Sixth 
Edition. 12mo, with nearly 100 Woodcuts and 3 Plates, cloth. $2.50 

THE STRAINS ON STRUCTURES OF IRONWORK. 

With Practical Remarks on Iron Construction. By F. W. Shields, 
M.Inst.C.E. 8vo, cloth $2.00 

CONSTRUCTIONAL IRON AND STEEL WORK, 

As applied to Public, Private, and Domestic Buildings. By Francis 
Campin, C.E. 12mo, cloth $1.40 



18 CROSBY LOCKWOOD &• SON'S CATALOGUE. 
MATERIALS AND CONSTRUCTION. 

A Theoretical and Practical Treatise on the Strains, Designing, and 
Erection of Works of Construction. By Francis Campin, C.E. Third 

Edition. 12mo, cloth as-i oft 

"No better exposition of the practical application of the principles of 

construction has yet been published to our knowledge in such a cheap 

comprehensive form." — Building News. 

EXPERIMENTS ON THE FLEXURE OF BEAMS. 

Resulting in the Discovery of New Laws of Failure by Buckling. By 
Albert E. Guy. Medium 8vo, cloth Net $1,25 

TRUSSES OF WOOD AND IRON. 

Practical Applications of Science in Determining the Stresses, Breaking 
Weights, Safe Loads, Scantlings, and Details of Construction. With 
Complete Working Drawings. By W. Griffiths, Surveyor. Oblong, 

8vo, cloth. $1.80 

"This handy little book enters so minutely into every detail connected 

with the construction of roof trusses that no student need be ignorant of 

these matters." — Practical Engineer. 

CONSTRUCTION OF ROOFS, OF WOOD AND IRON: 

Deduced chiefly from the Works of Robison, Tredgold, and Humber. 

ByE.W. Tarn, M.A., Architect. Fourth Edition. 12mo, cloth. # g0 
"Mr. Tarn is so thoroughly master of his subject, that although the trea- 
tise was founded on the works of others he has given it a distinct value of 
his own. It will be found valuable by all students." — Builder. 

A TREATISE ON THE STRENGTH OF MATERIALS. 

With Rules for Application in Architecture, the Construction of Sus- 
pension Bridges, Railways, &c. By Peter Barlow, F.R.S. A new 
Edition, revised by his Sons, P. W. Barlow, F.R.S., and W. H. Barlow. 
F.R.S. ; to which are added, Experiments by Hodgkinson, Fairbairn, 
and Kirkaldy; and Formulae for calculating Girders, &c. Edited by 
Wm. Humber, A.M.Inst. C.E. 8vo, 400 pp., with 19 Plates and numer- 
ous Woodcuts, cloth $7.00 

"Valuable alike to the student, tyro, and the experienced practitioner, it 

will always rank in future as it has hitherto done, as the standard treatise 

on that particular subject." — Engineer. 

EXPANSION OF STRUCTURES BY HEAT. 

By John Keily, C.E., late of the Indian Public Works Department. 

12mo, cloth $1.50 

"The aim the author has set before him, viz., to show the effects of heat 
upon metallic and other structures, is a laudable one, for this is a branch of 
physics upon which the engineer or architect can find but little reliable and 
comprehensive data in books."— Builder. 

CIVIL ENGINEERING. 

By Henry Law, M.Inst. C.E. Including a Treatise on Hydraulic En- 
gineering by G. R. Burnell, M.Inst. C.E. Seventh Edition, revised, 
with Large Additions on Recent Practice by D. Kinnear Clark, 
M.Inst.C.E. 12mo, cloth $2.60 

GAS WORKS, 

Their Construction and Arrangement, and the Manufacture and Distri- 
bution of Coal Gas. By S. Hughes, C.E. Ninth Edition. Revised, 
with Notices of Recent Improvements by Henry O'Connor, A.M.Inst. 

C.E. 12mo, cloth $2.40 

"Of infinite service alike to manufacturers, distributors, and consumers." 



MARINE ENGINEERING, NAVIGATION, &c. i 9 
PNEUMATICS, 

Including Acoustics and the Phenomena of Wind Currents, for the use 
of Beginners. By Charles Tomlinson, F.R.S. 12mo, cloth. # gQ 

FOUNDATIONS AND CONCRETE WORKS. 

With Practical Remarks on Footings, Planking, Sand, Concrete, B6ton, 
Pile-driving, Caissons, and Cofferdams. By E. Dobson. 12mo. m QQ 

BLASTING AND QUARRYING OF STONE, 

For Building and other Purposes. With Remarks on the Blowing up of 
Bridges. By Gen. Sir J. Burgoyne, K.C.B. 12mo, cloth. .. . # gQ 

SAFE RAILWAY WORKING. 

A Treatise on Railway Accidents, their Cause and Prevention; with a 
Description of Modern Appliances and Systems. By Clement E. 

Stretton, C.E. Third Edition, Enlarged. 12mo, cloth $1.50 

"A book for the engineer, the directors, the managers; and, in short, all 

who wishfor information on railway matters will find a perfect encyclopedia 

in 'Safe Railway Working.'" — Railway Review. 



MARINE ENGINEERING, SHIPBUILDING, 
NAVIGATION, ETC. 



MARINE ENGINES AND BOILERS. 

Their Design and Construction. A Handbook for the Use of Students, 
Engineers, and Naval Constructors. Based on the Work "Berechnung 
und Konstruktion der Schiffsmaschinen und Kessel," by Dr. G. Bauer, 
Engineer-in-Chief of the Vulcan Shipbuilding Yard, Stettin. Translated 
from the Second German Edition by E. M. Donkin, and S. Bryan 
Donkin, A. M.I. C.E. Edited by Leslie S. Robertson, Secretary to 
the Engineering Standards Committee, M.I.C.E., M.I.M.E., M.I.N. A., 
&c. With numerous Illustrations and Tables. Thick 8vo, cloth, 

[Just Published. $9.00 
Summary of Contents:— PART I.— MAIN ENGINES.— Determina- 
tion of Cylinder Dimensions. — The Utilisation of Steam in the En- 
gine. — Stroke of Piston. — Number of Revolutions. — Turning Moment. 
— Balancing of the Moving Parts. — Arrangement of Main Engines. — 
Details of Main Engines. — The Cylinder. — Valves. — Various Kinds 
of Valve Gear. — Piston Rods. — Pistons. — Connecting Rod and Cross- 
head. — Valve Gear Rods. — Bed Plates. — Engine Columns. — Revers- 
ing and Turning Gear. PART II. — PUMPS. — Air, Circulating Feed, 
and Auxiliary Pumps. PART III.— SHAFTING, RESISTANCE OF 
SHIPS, PROPELLERS.— Thrust Shaft and Thrust Block.— Tunnel- 
Shafts and Plummer Blocks. — Shaft Couplings. — Stern Tube. — The 
Screw Propeller. — Construction of the Screw. PART IV. — PIPES 
AND CONNECTIONS.— General Remarks, Flanges, Valves, &c— 
Under Water Fittings. — Main Steam, Auxiliary Steam, and Exhaust 
Piping. — Feed Water, Bilge, Ballast and Circulating Pipes. PART 
V. — STEAM BOILERS. — Firing and the Generation of Steam. — 
Cylindrical Boilers. — Locomotive Boilers. — Water-tube Boilers. — 
Small Tube Water-Tube Boilers. — Smoke Box. — Funnel and Boiler 
Lagging. — Forced Draught. — Boiler Fittings and Mountings. 
PART VI.— MEASURING INSTRUMENTS. PART VII.— VARIOUS 
DETAILS. — Bolts, Nuts, Screw Threads, &c. — Platforms, Gratings, 
Ladders. — Foundations. — Seatings. — Lubrication. — Ventilation of 
Engine Rooms. — Rules for Spare Gear. PART VIII. — ADDITIONAL 
TABLES. 



20 CROSBY LOCKWOOD &• SON'S CATALOGUE. 

THE NAVAL ARCHITECT'S AND SHIPBUILDER'S 
POCKET=BOOK 

Of Formulae, Rules, and Tables, and Marine Engineer's and Surveyor's 
Handy Book of Reference. By Clement Mackrow, M.I.N. A. Eighth 
Edition, carefully Revised and Enlarged. Fcap, leather. . Net $5.00 
Summary of Contents: — Signs and Symbols, Decimal Fractions. — 
Trigonometry. — Practical Geometry. — Mensuration. — Centres and 
Moments op Figures. — Moments op Inertia and Radii Gyration. — Al- 
gebraical Expressions for Simpson's Rules. — Mechanical Principles. 
— Centre op Gravity. — Laws of Motion. — Displacement, Centre of 
Buoyancy. — Centre of Gravity of Ships' Hull. — Stability Curves and 
Metacentres. — Sea and Shallow-water Waves.— Rolling of Ships. — 
Propulsion and Resistance of Vessels. — Speed Trials. — Sailing, Cen- 
tre op Effort. — Distances down Rivers, Coast Lines. — Steering and 
Rudders of Vessels. — Launching Calculations and Velocities. — 
Weight op Material and Gear. — Gun Particulars and Weight. — 
Standard Gauges. — Riveted Joints and Riveting. — Strength and 
Tests op Materials. — Binding and Shearing Stresses. — Strength of 
Shafting, Pillars, Wheels, &c. — Hydraulic Data, &c. — Conic Sec- 
tions, Catenarian Curves. — Mechanical Powers, Work. — Board of 
Trade Regulations for Boilers and Engines. — Board op Trade Reg- 
ulations for Ships. — Lloyd's Rules for Boilers. — Lloyd's Weight of 
Chains. — Lloyd's Scantlings for Ships. — Data of Engines and Ves- 
sels. — Ships' Fittings and Tests. — Seasoning Preserving Timber. — 
Measurement of Timber. — Alloys, Paints, Varnishes. — Data for Stow- 
age. — Admiralty Transport Regulations. — Rules for Horse-power, 
Screw Propellers, &c. — Percentages for Butt Straps. — Particulars 
of Yachts. — Masting and Rigging. — Distances of Foreign Ports. — 
Tonnage Tables.— Vocabulary op French and English Terms. — English 
Weights and Measures. — Foregn Weights and Measures. — Decimal 
Equivalents. — Useful Numbers. — Circular Measures. — Areas of and 
Circumferences of Circles. — Areas of Segments of Circles. — Tables 
of Squares and Cubes and Roots of Numbers. — Tables of Logarithms 
of Numbers. — Tables op Hyberpolic Logarithms. — Tables of Natural 
Sines, Tangents. — Tables of Logarithmic Sines, Tangents, &c. 

WANNAN'S MARINE ENGINEER'S GUIDE 

To Board of Trade Examinations for Certificates of Competency. Con- 
taining all Latest Questions to Date, with Simple, Clear, and Correct 
Solutions; 302 Elementary Questions with Illustrated Answers, and 
Verbal Questions and Answers; complete Set of Drawings with State- 
ments completed. By A. C. Wannan, C.E., Consulting Engineer, and 
E. W. I. Wannan, M.I.M.E., Certificated First Class Marine Engineer. 
With numerous Engravings. Fourth Edition, Enlarged. 500 pages. 
8vo, cloth $4.00 

WANNAN'S MARINE ENGINEER'S POCKET=BOOK. 

Containing Latest Board of Trade Rules and Dataf or Marine Engineers. 
By A. C. Wannan. Third Edition, Revised, Enlarged, and Brought up 
to Date. Square 18mo, with thumb Index, leather $2.00 

MARINE ENGINES AND STEAM VESSELS. 

By R. Murray, C.E. Eighth Edition, thoroughly Revised, with Addi- 
tions by the Author and by George Carlisle, C.E. 12mo, cloth. $1.80 

ELEMENTARY MARINE ENGINEERING. 

A Manual for Young Marine Engineers and Apprentices. By J. S. 
Brewer. 12mo, cloth .60 

CHAIN CABLES AND CHAINS. 

Comprising Sizes and Curves of Links, Studs, &c, Iron for Cables and 
Chains, Chain Cable and Chain Making, Forming and Welding Links, 
Strength of Cables and Chains, Certificates for Cables, Marking Cables, 
Prices of Chain Cables and Chains, Historical Notes, Acts of Parlia- 
ment, Statutory Tests, Charges for Testing, List of Manufacturers of 



MARINE ENGINEERING, NAVIGATION, &c 21 

Cables, &c, &c. By Thomas W. Traill, F.E.R.N., M.Inst.C.E., En- 
gineer-Surveyor-in-Chief , Board of Trade, Inspector of Chain Cable and 
Anchor Proving Establishments, and General Superintendent, Lloyd's 
. Committee on Proving Establishments. With numerous Tables, Illus- 
trations, and Lithographic Drawings. Folio, cloth $15.00 

THE SHIPBUILDING INDUSTRY OF GERMANY. 

Compiled and Edited by G. Lehmann-Felskowski. With Coloured 
Prints, Art Supplements, and numerous Illustrations throughout the 
text. Super-royal 4to, cloth $4.20 

SHIPS AND BOATS. 

By W. Bland. With numerous Illustrations and Models. Tenth Edi- 
tion. 12mo, cloth # g0 

SHIPS FOR OCEAN AND RIVER SERVICE, 

Principles of the Construction of. By H. A. Sommerfeldt. 12mo. 

.60 

AN ATLAS OF ENGRAVINGS 

To iftustrate the above. Twelve large folding Plates. Royal 4to, 
doth $3.00 

NAVAL ARCHITECTURE. 

An Exposition of the Elementary Principles. By J. Peake. 12mo. 
doth $1.40 

THE ART AND SCIENCE OF SAIL/MAKING. 

By Samuel B. Sadler, Practical Sailmaker, late in the employment of 
Messrs. Ratsey and Lapthorne, of Cowes and Gosport. Plates. 4to, 

doth $5.00 

"This extremely practical work gives a complete education in all the 
branches of the manufacture, cutting out, roping, seaming, and goring. It 
s copiously illustrated, and forms a first-rate text-book and guide." 

SAILS AND SAIL=MAKING. 

With Draughting, and the Centre of Effort of the Sails. Weights and 
Sizes of Ropes; Masting, Rigging, and Sails of Steam Vessels, &c. By 
R. Kipping, N.A. 12mo, cloth $1.00 

MASTING, MAST=MAKING, AND RIGGING OF SHIPS. 

Also Tables of Spars, Rigging, Blocks; Chain, Wire, and Hemp Ropes, 
&c, relative to every class of vessels. By R. Kipping. 12mo, cloth, 

.SO 
SEA TERMS, PHRASES, AND WORDS 

(Technical Dictionary of) used in the English and French Languages 
(English- French, French-English). For the Use of Seamen, Engineers, 
Pilots, Shipbuilders, Shipowners, and Ship-brokers. Compiled by W. 
Pirrie, late of the African Steamship Company. Fcap, 8vo, cloth 

limp $3.00 

This volume will be highly appreciated by seamen, engineers, pilots, ship- 
builders and shipowners. It will be found wonderfully accurate and com- 
plete. 

SAILOR'S SEA BOOK: 

A Rudimentary Treatise on Navigation. By James Greenwood, B.A. 
With numerous Woodcuts and Coloured Plates. New and Enlarged 

Edition. By W. H. Rosser. 12mo, cloth $1.00 

Is perhaps the best and simplest epitome of navigation ever compiled. 

PRACTICAL NAVIGATION. 

Consisting of the Sailor's Sea Book, by J. Greenwood and W. H. Rosser; 
together with Mathematical and Nautical Tables for the Working of the 
Problems, by H. Law, C.E., and Prof. J. R. Young $2.80 



22 CROSBY LOCKWOOD & SON'S CATALOGUE. 
NAVIGATION AND NAUTICAL ASTRONOMY, 

In Theory and Practice. By Prof. J. R. Young. 12mo, cloth.$1.00 
"A very complete, thorough, and useful manual for the young navigator." 

MATHEMATICAL TABLES, 

For Trigonometrical, Astronomical, and Nautical Calculations; to 
which is prefixed a Treatise on Logarithms, by H. Law, C.E. With 
Tables for Navigation and Nautical Astronomy. By Prof. J. R. Young. 
12mo, cloth $1.60 



MINING, METALLURGY, AND 
COLLIERY WORKING. 



THE OIL FIELDS OF RUSSIA AND THE RUSSIAN 

PETROLEUM INDUSTRY. 

A Practical Handbook on the Exploration, Exploitation, and Manage- 
ment of Russian Oil Properties, including Notes on the Origin of Petro- 
leum in Russia, a Description of the Theory and Practice of Liquid 
Fuel, and a Translation of the Rules and Regulations concerning Rus- 
sian Oil Properties. By A. Beeby Thompson, A.M.I.M.E., late Chief 
Engineer and Manager of the European Petroleum Company's Russian 
Oil Properties. About 500 pp. With numerous Illustrations and 
Photographic Plates, and a Map of the Balakhany-Saboontchy-Romany 
Oil Field. Royal 8vo, cloth Net $ 7.50 

MECHANICS OF AIR MACHINERY. 

By Dr. J. Weisbach and Prof. G. Herrmann. Authorized Translation 
with an Appendix on American Practice by A. Trowbridge, Ph.B., 
Adjunct Professor of Mechanical Engineering, Columbia University. 

Royal 8vo, cloth [Just Published. Net $3.7o 

Summary of Contents : — The Movement of Air. — Natural and Arti- 
ficial Ventilation. — Blowing-Engines; — Vacuum Pumps; Tuyeres; 
Hot-air Blast; Work Performed by Blowers; Blast-reservoirs; 
Piston-blowers. — Compressors. — Rotary Blowers. — Fans. — Recent 
American Practice, &c. 

MACHINERY FOR METALLIFEROUS MINES. 

A Practical Treatise for Mining Engineers, Metallurgists, and Managers 
of Mines. By E. Henry Da vies, M.E., F.G.S. 600 pp. With Fold- 
ing Plates and other Illustrations. Medium 8vo, cloth $8.00 

"Deals exhaustively with the many and complex details which go to 
make up the sum total of machinery and other requirements for the success- 
ful working of metalliferous mines, and as a book of ready reference is of 
the highest value to mine managers and directors." — Mining Journal. 

THE DEEP LEVEL MINES OF THE RAND, 

And their Future Development, considered from the Commercial Point 
oi View. By G. A. Denny (of Johannesburg), M.N.E.I.M.E., Con- 
sulting Engineer to the General Mining and Finance Corporation, Ltd., 
of London, Berlin, Paris, and Johannesburg. Fully Illustrated with 

Diagrams and Folding Plates. Royal 8vo, buckram $10.00 

"Mr. Denny by confining himself to the consideration of the future of the 
deep-level mines of the Rand breaks new ground, and by dealing with the 
subject rather from a commercial standpoint than from a scientific one, 
appeals to a wide circle of readers. The book cannot fail to prove of very 
great value to investors in South African mines." — Mining Journal. 



MINING, METALLURGY, & COLLIERY WORKING. 23 
PROSPECTING FOR GOLD. 

A Handbook of Practical Information and Hints for Prospectors based 
on Personal Experience. By Daniel J. Rankin, F.R.S.G.S., M.R.A.S., 
formerly Manager of the Central African Company, and Leader of 
African Gold Prospecting Expeditions. With Illustrations specially 

Drawn and Engraved for the Work. Fcap. 8vo, leather $L$.0l) 

" This well-compiled book contains a collection of the richest gems of use- 
ful knowledge for the prospector's benefit. A special table is given to 
accelerate the spotting at a glance of minerals associated with gold." — Min- 
,ng Journal. 

THE METALLURGY OF GOLD. 

A Practical Treatise on the Metallurgical Treatment of Gold-bearing 
Ores. Including the Assaying, Melting, and Refining of Gold. By M. 
Eissler, M.Inst.M.M. Fifth Edition, Enlarged. With over 300 Illus- 
trations and numerous Folding Plates. Medium 8vo, cloth. . • Jjj>7.50 
"This book thoroughly deserves its title of a 'Practical Treatise.' The 
whole process of gold mining, from the breaking of the quartz to the assay 
of the bullion, is described in clear and orderly narrative and with much 
fulness oWetail." 

THE CYANIDE PROCESS OF GOLD EXTRACTION, 

And its Practical Application on the Witwatersrand Gold Fields and 
elsewhere. By M. Eissler, M.Inst.M.M. With Diagrams and Work- 
ing Drawings, Third Edition, Revised and Enlarged. 8vo, cloth, 

$3.00 

"This book is just what was needed to acquaint mining men with the 
actual working of a process which is not only the most popular, but is, as 
a general rule, the most successful for the extraction of gold from tailings." 
— Mining Journal. 

DIAMOND DRILLING FOR GOLD & OTHER MINERALS. 

A Practical Handbook on the Use of Modern Diamond Core Drills in 
Prospecting and Exploiting Mineral-Bearing Properties, including Par- 
ticulars of the Costs of Aoparatus and Working. By G. A. Denny, 
M.N.E.Inst.M.E., M.Inst.M.M. Medium 8vo, 168 pp., with Illustra- 
tive Diagrams $5.00 

"There is certainly scopo for a work on diamond drilling, and Mr. Denny 

deserves grateful recognition for supplying a decided want." — Mining 

Journal. - 



GOLD ASSAYING. 

A Practical Handbook, giving the Modus Operandi for the Accurate 
Assay of Auriferous Ores and Bullion, and the Chemical Tests required 
in the Processes of Extraction by Amalgamation, Cyanidation, and 
Chlorination. With an Appendix of Tables and Statistics. By H. 
Joshua Phillips, F.I.C., F.C.S., Assoc Inst.C.E., Author of "Engineer- 
ing Chemistry," <kc. With numerous Illustrations. 12mo, cloth. $3.00 

FIELD TESTING FOR GOLD AND SILVER. 

A Practical Manual for Prospectors and Miners. By W. H. Merritt, 
M.N.E.Inst.M.E., A.R.S.M., &c. With Photographic Plates and other 

Illustrations. Fcap. 8vo, leather $1.50 

'As an instructor of prospectors' classes Mr. Merritt has the advantage of 
knowing exactlv the information likely to be most valuable to the miner 
in the field. The contents cover all the details for sampling and testing 
gold and silver ores. A useful addition to a prospector's kit." — Mining 
Journal. 



24 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
THE PROSPECTOR'S HANDBOOK. 

A Guide for the Prospector and Traveller in search of Metal-Bearing or 
other Valuable Minerals. By J. W. Anderson, M.A.(Camb.)> F.R.G.S. 

Tenth Edition. 12mo, cloth $1 .50 

"How to find commercial minerals, and how to identify them when they 

are found, are the leading points to which attention is directed." — Mining 

Journal. 

THE METALLURGY OF SILVER. 

A Practical Treatise on the Amalgamation, Roasting, and Lixiviation 
of Silver Ores. Including the Assaying, Melting, and Refining of Silver 
Bullion. By M. Eisslek, M.Inst.M.M. Fifth Edition. 12mo, cloth. 

$4.00 

"A practical treatise and a technical work which we are convinced will 

supply a long-felt want amongst practical men, and at the same time be of 

value to students and others indirectly connected with the industries." — 

Mining Journal. 

THE HYDRO=METALLURQY OF COPPER. 

Being an Account of Processes Adopted in the Hydro-Metallurgical 
Treatment of Cupriferous Ores, Including the Manufacture of Copper 
Vitriol, with ■ Chapters on the Sources of Supply of Copper and the 
Roasting of Copper Ores. By M. Eissler, M.Inst.M.M. 8vo, cloth, 

$4.50 
"In this volume the various processes for the extraction of copper by wet 
methods are fully detailed. Costs are given when available, and a great 
deal of useful information about the copper industry of the world is pre- 
sented in an interesting and attractive manner." — Mining Journal. 

THE METALLURGY OF ARGENTIFEROUS LEAD. 

A Practical Treatise on the Smelting of Silver-Lead Ores and the Refin- 
ing of Lead Bullion. Including Reports on various Smelting Estab- 
lishments and Descriptions of Modern Smelting Furnaces and Plants 
in Europe and America. By M. Eissler, M.Inst.M.M. 12mo, cloth 

$5.00 

"The numerous metallurgical processes, which are fully and extensively 

treated of, embrace all the stages experienced in the passage of the lead 

from the various natural states to its issue from the refinery as an article 

of commerce." — Practical Engineer. 

METALLIFEROUS MINERALS AND MINING. 

By D. C. Davies, F.G.S. Sixth Edition, thoroughly Revised and much 
Enlarged by his Son, E. Henry Davies, M.E., F.G.S. 600 pp., with 

173 Illustrations. 8vo, cloth Net $5.00 

"Neither the practical miner nor the general reader, interested in mines, 
can have a better book for his companion and his guide." — Mining Journal. 

EARTHY AND OTHER MINERALS AND MINING. 

By D. C. Davies, F.G.S., Author of "Metalliferous Minerals," &c. 
Third Edition, Revised and Enlarged by his Son, E. Henry Davies, 
M.E., F.G.S. With about 100 Illustrations. 12mo, cloth $5.00 

BRITISH MINING. 

A Treatise on the History, Discovery, Practical Development, and 
Future Prospects of Metalliferous Mines in the United Kingdom. By 
Robert Hunt, F R.S., late Keeper of Mining Records. Upwards of 
950 pp., with 230 Illustrations. Second Edition, Revised. Super-royal 
8vo, cloth $15.00 

POCKET=BOOK FOR MINERS AND METALLURGISTS. 

Comprising Rules, Formulae, Tables, and Notes for Use in Field and 
Office Work. By F. Danvers Power, F.G.S., M.E. Second Edition, 
Corrected. Fcap. 8vo, leather $3.50 



MINING, METALLURGY, &> COLLIERY WORKING. 25 
THE MINER'S HANDBOOK. 

A Handy Book of Reference on the subjects of Mineral Deposits, Mining 
Operations, Ore Dressing, &c. For the Use of Students and others in- 
terested in Mining Matters. Compiled by John Milne, F.R.S., Pro- 
fessor of Mining in the Imperial University of Japan. Third Edition. 
Fcap. 8vo, leather $3.00 

IRON ORES of GREAT BRITAIN and IRELAND. 

Their Mode of Occurrence, Age and Origin, and the Methods of Searching 
for and Working Them. With a Notice of some of the Iron Ores of 
Spain. By J. D. Kendall, F.G.S., Mining Engineer. 12mo, cloth 

$6.00 
METALLURGY OF IRON. 

Containing History of Iron Manufacture, Methods of Assay, and Analy- 
ses of Iron Ores, Processes of Manufacture of Iron and Steel, &c. By 
H. Bauerman, F.G.S., A.R.S.M. With numerous Illustrations. Sixth 

Edition, revised and enlarged. 12mo, cloth $2.00 

"Carefully written, it has the merit of brevity and conciseness, as to less 

important points; while all material matters are very fully and thoroughly 

entered into." — Standard. 

MINE 0RAINAGE. 

A Complete Practical Treatise on Direct-Acting Underground Steam 
Pumping Machinery. By Stephen Michell. Second Edition, Re- 
written and Enlarged. With 250 Illustrations. Royal 8vo, cloth. 

$10.00 
HORIZONTAL PUMPING ENGINES— Rotary and Non-Rotary 
Horizontal Engines. — Simple and Compound Steam Pumps. — VERTI- 
CAL PUMPING ENGINES.— Rotary and Non-Rotary Vertical 
Engines. — Simple and Compound Steam Pumps. — Triple-Expansion 
Steam Pumps. — Pulsating Steam Pumps. — Pump Valves. — Sinking 
Pumps, &c, &c. 

ELECTRICITY AS APPLIED TO MINING. 

By Arnold Lupton, M.Inst. C.E., M.I.M.E., M.I.E.E., late Professor of 
Coal Mining at the Yorkshire College, Victoria University, Mining En- 
gineer and Colliery Manager; G. D. Aspinall Parr, M.I.E.E., A.M.I. 
M.E., Associate of the Central Technical College, City and Guilds of 
London, Head of the Electrical Engineering Department, Yorkshire 
College, Victoria University; and Herbert Perkin, M.I.M.E., Certifi- 
cated Colliery Manager, Assistant Lecturer in the Mining Department of 
the Yorkshire College, Victoria University. With about 170 Illustra- 
tions. Second Edition, Revised and Enlarged. Medium 8vo, cloth. 

[Just Published.] $4.50 
(For Summary op Contents, see page 28.) 

THE COLLIERY MANAGER'S. HANDBOOK. 

A Comprehensive Treatise on the Laying-out and Working o'f Collieries, 
Designed as a Book of Reference for Colliery Managers, and for the 
Use of Coal-Mining Students preparing for First-class Certificates. By 
Caleb Pamely, Mining Engineer and Surveyor; Member of the North 
of England Institute of Mining and Mechanical Engineers ; and Member 
of the South Wales Institute of Mining Engineers. With over 1,000 
Diagrams, Plans, and other Illustrations. Fifth Edition, Carefully 
Revised and Greatly Enlarged. 1,200 pp. Medium 8vo, cloth. $10.00 
Geology. — Search for Coal. — Mineral Leases and other Holdings. — 
Shaft Sinking. — Fitting Up the Shaft and Surface Arrangements. — 
Steam Boilers and their Fittings. — Timbering and Walling. — Narrow 
Work and Methods of Working. — Underground Conveyance. — Drain- 
age. — The Gasks met with in Mines; Ventilation. — On the Friction of 
Air in Mines. — The Priestman Oil Engine; Petroleum and Natural 
Gas. — Surveying and Planning. — Safety Lamps and Firedamp Detect- 
ors. — Sundry and Incidental Operations and Appliances. — Colliery 
Explosions. — Miscellaneous Questions and Answers. — Appendix: 
Summary of Report of H.M. Commissioners on Accidents in Mines, 



26 CROSBY LOCKWOOD 6* SON'S CATALOGUE. 
PRACTICAL COALMINING. 

An Elementary Class-Book for the Use of Students attending Classes in 
Preparation for the Board of Education and County Council Examina- 
tions, or Qualifying for First or Second Class Colliery Managers' Cer- 
tificates. By. T. H. Cockin, Member ot the Institution of Mining 
Engineers, Certificated Colliery Manager, Lecturer on Coal-Mining at 
Sheffield University College. With Map of the British Coal-fields and 
over 200 Illustrations specially Drawn and Engraved for the Work. 
440 pp., 12mo, cloth $2.50 

COLLIERY WORKING AND MANAGEMENT. 

Comprising the Duties of a Colliery Manager, the Oversight and Arrange- 
ment of Labour and Wages, and the different Systems of Working Coal 
Seams. By H. F. Bulman and R. A. S. Redmayne. 350 pp., with 
28 Plates and other Illustrations, including Underground Photographs. 
Medium 8vo, cloth Net $6.00 

NOTES AND FORMUL/E FOR MINING STUDENTS. 

By John Herman Merivale, M.A., Late Professor of Mining in the 
Durham College of Science, Newcastle-upon-Tyne. Fourth Edition, 
Revised and Enlarged. By H. F. Btjlman, A.M. Inst. C.E. 12mo, 

doth $1.00 

"The author has done his work in a creditable manner, and has produced 

a book that will be of service to students and those who are practically 

engaged in mining operations." — Engineer. 

PHYSICS AND CHEMISTRY OF MINING. 

An Elementary Class-Book for the use of Students preparing for the 
Board of Education and County Council Examinations in Mining, or 
Qualifying for Colliery Managers' Certificates. By T. H. Byrom, 
Chemist to the Wigan Coal and Iron Co., Ltd., &c. With Illustrations. 
12mo, cloth [Just Published.] $1.50 

MINING CALCULATIONS. 

For the use of Students Preparing for the Examinations for Colliery 
Managers' Certificates, comprising Numerous Rules and Examples in 
Arithmetic, Algebra, and Mensuration. By T. A. O'Donahue, M.E., 
First-class Certificated Colliery Manager. 12mo, cloth $1.50 

COAL AND COAL MINING. 

By the late Sir Warington W. Smyth, M.A., F.R.S. Eighth Edition, 
Revised and Extended by T. Forster Brown, Chief Inspector of the 
Mines of the Crown and of the Duchy of Cornwall. 12mo, cloth. $1.40 

INFLAMMABLE GAS AND VAPOUR IN THE AIR 

(The Detection and Measurement of). By Frank Clowes, D.Sc, 
Lond., F.I.C. With a Chapter on The Detection and Measurement 
of Petroleum Vapour, by Boverton Redwood, F.R.S.E. 12mo, 

doth $2.50 

' ' Professor Clowes has given us a volume on a subject of much industrial 
importance. . . Those interested in these matters may be recommended 
to study this book, which is easy of comprehension and contains many good 
things." — The Engineer. 

COAL & IRON INDUSTRIES of the UNITED KINGDOM. 

Comprising a Description of the Coal Fields and of the Principal Seams 
of Coal, with Returns of their Produce and its Distribution, and Analyses 
of Special Varieties. Also, an Account of the Occurrence of Iron Ore 
in Veins or Seams; Analyses of each Variety; and a History of the 
Rise and Progress of Pig Iron Manufacture. By Richard Meade. 8vo, 
cloth $10.00 



MINING, METALLURGY, & COLLIERY WORKING. 27 
MINING TOOLS, 

Manual of. By W. Morgans, Lecturer on Mining at the Bristol School 
of Mines. 12mo, cloth ffi ]_ t QQ 

Atlas of Engravings to the above, containing 235 Illustrations drawn 
to Scale. 4to $1.80 

SLATE AND SLATE QUARRYING. 

Scientific, Practical, and Commercial. By D. C. Davies, F.G.S., Min- 
ing Engineer, &c. With numerous Illustrations and Folding Plates 
Fourth Edition. 12mo, cloth $1.20 

A FIRST BOOK OF MINING AND QUARRYING. 

By J. H. Collins, F.G.S. Crown 8vo, cloth t g Q 

ASBESTOS AND ASBESTIC. 

Their Properties, Occurrence, and Use. By Robert H. Jones, F.S.A. 
Mineralogist, Hon. Mem. Asbestos Club, Black Lake, Canada. With 
Ten Collotype Plates and other Illustrations. Demy 8vo, cloth. $6.40 

GRANITES AND OUR GRANITE INDUSTRIES. 

By George F. Harris, F.G.S. With Illustrations. 12mo, cloth. $1.00 

MINERAL SURVEYOR AND VALUER'S GUIDE. 

Comprising a Treatise on Improved Mining Surveying and the Valuation 
of Mining Properties, with New Traverse Tables. By W. Lintern, C.E. 

Fourth Edition, enlarged. 12mo, cloth $1.40 

"Contains much valuable information, and is thoroughly trustworthy." — 
Iron and Coal Trades Review. 

TRAVERSE TABLES. 

For use in Mine Surveying. By William Lintern, C.E. With two 
plates. Small crown 8vo, cloth Net $1.50 

SUBTERRANEOUS SURVEYING. 

By T. Fenwick. Also the Method of Conducting Subterraneous Sur- 
veys without the use of the Magnetic Needle, &c. By T.Baker. 12mo, 

$1.00 

MINERALOGY, 

Rudiments of. By A. Ramsay, F.G.S. Fourth Edition. Woodcuts 
and Plates. 12mo, cloth $1.40 

PHYSICAL GEOLOGY, 

Partly based on Major-General Portlock's "Rudiments of Geology." 
By Ralph Tate, A.L.S., &c. Woodcuts. 12mo, cloth .80 

HISTORICAL GEOLOGY, 

Partly based on Major-General Portlock's "Rudiments." By Ralph 
Tate. 12mo, cloth $1.00 

GEOLOGY, 

Physical and Historical. Consisting of "Physical Geology," which 
sets forth the Leading Principles of the Science; and "Historical Geol- 
ogy," which treats of the Mineral and Organic Conditions of the Earth 
at each successive epoch. By R. Tate. 12mo, cloth $1.80 



28 CROSBY LOCKWOOD & SON'S CATALOGUE. 



ELECTRICITY, ELECTRICAL 
ENGINEERING, ETC. 



THE ELEMENTS OF ELECTRICAL ENGINEERING. 

A First Year's Course for Students. By Tyson Sewell, A.I.E.E., 
Assistant Lecturer and Demonstrator in Electrical Engineering at the 
Polytechnic, Regent Street, London. Third Edition, Revised and En- 
larged, including an Appendix of Questions and Answers. 460 pages, 
with 274 Illustrations. Demy 8vo, cloth. . . .[Just Published.] §3.00 
Ohm's Law. — Units Employed in Electrical Engineering. — Series, 
and Parallel Circuits; Current Density and Potential Drop in the. 
Circuit. — The Heating Effect of the Electric Current. — The Mag- 
netic Effect of an Electric Current. — The Magnetisation of Iron. — 
Electro-Chemistry; Primary Batteries. — Accumulators. — Indicat- 
ing Instruments; Ammeters, Voltmeters, Ohmmeters. — Electricity 
Supply Meters. — Measuring Instruments, and the Measurement of 
Electrical Resistance. — Measurement of Potential Difference 
Capacity Current Strength, and Permeability. — Arc Lamps. — Incan- 
descent Lamps, Manufacture and Installation; Photometry. — The 
Continuous Current Dynamo. — Direct Current Motors. — Alternating 
Currents. — Transformers, Alternators, Synchronous Motors. — Poly- 
phase Working. — Appendix of Questions and Answers. 

ELEMENTARY ELECTRICAL ENGINEERING 

In Theory and Practice. A Class-book for Junior and Senior Students 
and Working Electricians. By J. H. Alexander, M.B., A.I.E.E 
With 181 Illustrations. 12mo, cloth [Just Published. $1.50 

THE ELECTRICAL TRANSMISSION OF ENERGY. 

A Manual for the Design of Electrical Circuits. By Arthur Vaughan 
Abbott, C.E., Member American Institute of Electrical Engineers, 
Member American Institute of Mining Engineers, Member American 
, Society of Civil Engineers, Member American Society of Mechanical 
Engineers, &c. With Ten Folding Diagrams and Sixteen Full-page 
Engravings. Fourth Edition, entirely Re- Written and Enlarged. 
Royal 8vo, cloth Net $5.00 

ELECTRICITY AS APPLIED TO MINING. 

By Arnold Lupton, M.Inst.C.E., M.I.M.E., M.I.E.E., late Professor of 
Coal Mining at the Yorkshire College, Victoria University, Mining En- 
gineer and Colliery Manager; G. D. Aspinall Parr, M.I.E.E., A.M.I. 
M.E., Associate of the Central Technical College, City and Guilds of 
London, Head of the Electrical Engineering Department, Yorkshire 
College, Victoria University; and Herbert Perkin, M.I.M.E., Cer- 
tificated Colliery Manager, Assistant Lecturer in the Mining Depart- 
ment of the Yorkshire College, Victoria University. With about 170 
Illustrations. Second Edition, Revised and Enlarged, Medium 8vo, 

cloth [Just Published. $4.50 

Introductory. — Dynamic Electricity. — Driving of the Dynamo. — 
The Steam Turbine. — Distribution of Electrical Energy. — Starting 
and Stopping Electrical Generators and Motors. — Electric Cables. — 
Central Electrical Plants. — Electricity applied to Pumping and 
Hauling. — Electricity applied to Coal-cutting. — Typical Electric 
Plants Recently Erected. — Electric Lighting by Arc and Glow 
Lamps. — Miscellaneous Applications of Electricity. — Electricity as 
Compared with other modes of Transmitting Power. — Dangers of 
Electricity. 



ELECTRICITY, ELECTRICAL ENGINEERING, &c. 29 
CONDUCTORS FOR ELECTRICAL DISTRIBUTION. 

Their Materials and Manufacture, The Calculation of Circuits, Pole-Line 
Construction, Underground Working, and other Uses. By F. A. C. 
Perbine, A.M., D.Sc; formerly Professor of Electrical Engineering, 
Leland Stanford, Jr., University; M.Amer.I.E.E. 8vo, cloth. 

Net $3.50 
Conductor Materials. — Alloyed Conductors. — Manufacture of 
Wire. — Wire-Finishing. — Wire Insulation. — Cables. — Calculation of 
Circuits. — Kelvin's Law of Economy in Conductors. — Multiple Arc 
Distribution. — Alternating Current Calculation. — Overhead Lines. 
— Pole Line. — Line Insulators. — Underground Conductors. 

DYNAMO ELECTRIC MACHINERY: its CONSTRUC= 
TION, DESIGN, and OPERATION. 

By Samuel Sheldon, A.M., Ph.D., Professor of Physics and Electrical 
Engineering at the Polytechnic Institute of Brooklyn, assisted by H. 
Mason. B.S. 

In two volumes, sold separately, as follows: — 
Vol. I.— DIRECT CURRENT MACHINES. Fifth Edition, Revised. 

8vo. 280 pages, with 200 Illustrations -N^$2.50 

Vol. U— ALTERNATING CURRENT MACHINES. 8vo. 260 pages, 

with 184 Illustrations Net $2.50 

Designed as Text-books for use in Technical Educational Institutions, and 
by Engineers whose work includes the handling of Direct and Alternating 
Current Machines respectively, and for Students proficient in mathematics. 

DYNAMO, MOTOR AND SWITCHBOARD CIRCUITS 
FOR ELECTRICAL ENGINEERS. 

A Practical Book dealing with the subject of Direct, Alternating and 
Polyphase Currents. By William R. Bowker, C.E., M.E., E.E., Con- 
sulting Tramway Engineer. 8vo, cloth $2.25 

"Mr. Bowker's book consists chiefly of diagrams of connections, with short 
explanatory notes, there are over 100 diagrams, and the cases considered 
cover all the more important circuits, whether in direct current, single- 
phase, or polyphase work." — Nature. 

ARMATURE WINDINGS OF DIRECT CURRENT 
DYNAMOS. 

Extension and Application of a General Winding Rule. By E. Arnold, 
Translated from the German by F. B. De Grees. 8vo, cloth. $2.00 

POWER TRANSMITTED BY ELECTRICITY, 

And applied by the Electric Motor, including Electric Railway Con- 
struction. By P. Atkinson, A.M., Ph.D. Third Edition, Fully Re- 
vised, and New Matter added. With 94 Illustrations. 12mo, cloth. 

$2.00 
DYNAMO CONSTRUCTION. 

A Practical Handbook for the Use of Engineer-Constructors and Elec- 
tricians-in-Charge. Embracing Framework Building, Field Magnet and 
Armature Winding and Grouping, Compounding, &c. By J. W. Urqu- 
hart. Second Edition, Enlarged, with 114 Illustrations. 12mo, cloth. 

$3.00 

HOW TO MAKE A DYNAMO. 

A Practical Treatise for Amateurs. Containing Illustrations and De- 
tailed Instructions for Constructing a Small Dynamo to Produce the 
Electric Light. By Alfred Crofts. Seventh Edition. 12mo, cloth. 

.80 

WIRELESS TELEGRAPHY; 

Its Origins, Development, Inventions, and Apparatus. By Charles 
Henry Sewall. With 85 Diagrams and Illustrations. 8vo, cloth. 

Net $2.00 



30 CROSBY LOCKWOOD &» SON'S CATALOGUE. 
SUBMARINE TELEGRAPHS; 

Their History, Construction, and Working. Founded in part on Wun- 
schendorff t s ' ' Traits de Telegraphie Sous-Marine," and Compiled from 
Authoritative and Exclusive Sources. By Charles Bright, F.R.S.E. 
A.M.Inst.C.E., M.I.E.E. 780 pp., fully Illustrated, including Maps and 
Folding Plates. Royal 8vo, cloth $25.00 

ELECTRICAL AND MAGNETIC CALCULATIONS. 

For the Use of Electrical Engineers and Artisans, Teachers, Students, 
and all others interested in the Theory and Application of Electricity 
and Magnetism. By Prof. A. A. Atkinson, Ohio University. 12mo, 
doth. . $1.50 

"To teachers and those who already possess a fair knowledge of their sub- 
ject we can recommend this book as being useful to consult when requiring 
data or formulae which it is neither convenient nor necessary to retain by 
memory." — The Electrician. 

THE ELECTRICAL ENGINEER'S POCKET=BOOK. 

Consisting of Rules, Formulae, Tables, and Data. By H. R. Kemfe, 
M.I.E.E., A.M.Inst.C.E., Technical Officer Postal Telegraphs, Author 
of "A Handbook of Electrical Testing." Second Edition. 32mo, 
leather $1.75 

ELECTRIC LIGHTING (ELEMENTARY PRINCIPLES OF). 

By Alan A. Campbell Swinton, M.Inst.C.E., M.I.E.E. Sixth Edition. 
With 16 Illustrations. 12mo, cloth .60 

ELECTRIC LIGHT. 

Its Production and Use, Embodying Plain Directions for the Treatment 
of Dynamo-Electric Machines, Batteries, Accumulators, and Electric 
Lamps. By J. W. Urquhart, C.E. Seventh Edition. 12mo, cloth. 

$3.00 

ELECTRIC LIGHT FOR COUNTRY HOUSES. 

A Practical Handbook on the Erection and Running of Small Installa- 
tions, with Particulars of the Cost of Plant and Working. By J. H. 
Knight. Fourth Edition, Revised. 12mo, boards 50 

ELECTRIC LIGHT FITTING. 

A Handbook for Working Electrical Engineers, embodying Practical 
Notes on Installation Management. By J. W. Urquhart. With 
numerous Illustrations. Fourth Edition, Revised. 12mo, cloth. $2.00 

ELECTRIC SHIP=LIGHTING. 

A Handbook on the Practical Fitting and Running of Ships' Electrical 
Plant. For the Use of Shipowners and Builders, Marine Electricians, 
and Seagoing Engineers-in-Charge. By J. W. Urquhart, C.E. Third 
Edition, Revised and Extended. With 88 Illustrations, 12mo, 
cloth $3.00 

DYNAMIC ELECTRICITY AND MAGNETISM. 

By Philip Atkinson, A.M., Ph.D., Author of "Elements of Static 
Electricity," &c. Crown, 8vo, 417 pp., with 120 Illustrations, cloth 

$2.00 

THE STUDENT'S TEXT=BOOK OF ELECTRICITY. 

By H. M. Noad, F.R.S. 650 pp., with 470 Illustrations. 12mo, 
cloth ' $4.00 



ARCHITECTURE, BUILDING, &>c. 31 

ARCHITECTURE, BUILDING, ETC. 



SPECIFICATIONS IN DETAIL. 

By Frank W. Macey, Architect, Author of "Conditions of Contract." 
Second Edition, Revised and Enlarged, containing 644 pp., and 2,000 

Illustrations. Royal 8vo, cloth $8.00 

Summary of Contents: — General Notes (including Points in Speci- 
fication Writing, The Order of a Specification, and Notes on Items 
often Omitted from a Specification). — Form of Outside Cover to a 
Specification. — Specification of Works and List of General Condi- 
tions. — Preliminary Items (including Shoring and House Breaker). 
— Drainage (including Rain-water Wells and Reports). — Excavator 
(including Concrete Floors, Roofs, Stairs, and Walls). — Pavior. — 
Bricklayer (including Flintwork, River, and other Walling, Spring- 
water Wells, Storage Tanks, Fountains, Filters, Terra Cotta and 
Faience). — Mason. — Carpenter, Joiner, and Ironmonger (including 
Fencing and Piling). — Smith and Founder (including Heating, Fire 
Hydrants, Stable and Cow-house Fittings). — Slater (including Slate 
Mason^i- — Tiler. — Stone Tiler. — Shingler. — Thatcher. — Plumber (in- 
cluding Hot-water Work). — Zincworker. — Coppersmith. — Plasterer. 
— Gasfitter. — Bellhanger. — Glazier. — Painter. — Paperhanger. — 
General Repairs and Alterations. — Ventilation. — Road-making. — 
Electric Light. — Index. 

PRACTICAL BUILDING CONSTRUCTION. 

A Handbook for Students Preparing for Examinations, and a Book 
of Reference for Persons Engaged in Building. By John Parnell 
Allen, Surveyor, Lecturer on Building Construction at the Durham 
College of Science, Newcastle-on-Tyne. Fourth Edition, Revised and 
Enlarged. Medium 8vo, 570 pp., with over 1,000 Illustrations, cloth, 

$3.00 

SPECIFICATIONS FOR PRACTICAL ARCHITECTURE. 

A Guide to the Architect, Engineer, Surveyor, and Builder. Upon 
the Basis of the Work by A. Bartholomew, Revised, by F. Rogers. 
8vo, cloth. ..-. $6.00 

SCIENCE OF BUILDING: 

An Elementary Treatise on the Principles of Construction. By E. 
Wyndham Tarn, M.A.Lond. Fourth Edition. 12mo, cloth. $1.40 

ART OF BUILDING, 

Rudiments of. General Principles of Construction , Character, Strength, 
and Use of Materials, Preparation of Specifications and Estimates, &c. 
By Edward Dobson, M.Inst.C.E. Fifteenth Edition, revised by J. P. 
Allen, Lecturer on Building Construction at the Durham College of 
Science. 12mo, cloth ,80 

BOOK ON BUILDING, 

Civil and Ecclesiastical. By Sir Edmund Beckett, Bart., LL.D. 
Second Edition. 12mo, cloth $1.80 

BUILDING ESTATES: 

A Treatise on the Development, Sale, Purchase, and Management of 
Building Land. By F. Maitland. Fourth Edition. 12mo, cloth, 

.80 
COTTAGE BUILDING. 

By C. Bruce Allen. Twelfth Edition, with Chapter on Economic 
Cottages for Allotments by E. E. Allen, C.E. 12mo, cloth. . .80 



32 CROSBY LOCKWOOD 6- SON'S CATALOGUE. 
DWELLING=HOUSES, 

Erection of, illustrated by a Perspective View, Plans, Elevations, and 
Sections of a Pair of Villas, with the Specification, Quantities, and 
Estimates. By S. H. Brooks. 12mo, cloth «aj qq 

FARM BUILDINGS: 

Their Arrangement and Construction, with Plans and Estimates. By 
Professor J. Scott. 12mo, cloth # gQ 

SHORING, 

And its Application. By G. H. Blagrove. Crown 8vo, cloth. m QQ 

ARCHES, PIERS, BUTTRESSES. 

By William Bland. 12mo, cloth # gQ 

PRACTICAL BRICKLAYING. 

General Principles of Bricklaying; Arch Drawing, Cutting, and Setting; 
Pointing; Paving, Tiling, &c. By Adam Hammond. With 68 Wood- 
cuts. 12mo, cloth m QQ 

ART OF PRACTICAL BRICK=CUTTING AND SETTING. 

By Adam Hammond. With 90 Engravings. 12mo, cloth. . . . # gQ 

BRICKWORK: 

Embodying the General and Higher Principles of Bricklaying, Cutting, 
and Setting; with the Application of Geometry to Roof Tiling, <fec. 

By F. Walker. 12mo, cloth ^gQ 

"Contains all that a student needs to learn from books. — Building News." 

BRICKS AND TILES, 

Rudimentary Treatise on the Manufacture of. Containing an Outline 
of the Principles of Brickmaking. By E. Dobson, M.R.I.B.A. Addi 
tions by C. Tomlinson, F.R.S. Illustrated. 12mo, cloth. . . -$1.20 

PRACTICAL BRICK AND TILE BOOK. 

Comprising: Brick and Tile Making, by E. Dobson, M.Inst.C.E. ; Prac- 
tical Bricklaying by A. Hammond, Brick-Cutting and Setting, by A. 
Hammond. 550 pp., with 270 Illustrations, strongly half -bound. $2.40 

PRACTICAL MASONRY. 

A Guide to the Art of Stone Cutting. Comprising the Construction, 
Setting-Out, and Working of Stairs, Circular Work, Arches, Niches, 
Domes, Pendentives, Vaults, Tracery Windows, &c; to which are 
added Supplements relating to Masonry Estimating and Quantity Sur- 
veying, and to Building Stones and Marbles, and a Glossary of Terms. 
For the Use of Students, Masons, and Craftsmen. By W. R. Purchase, 
Building Inspector to the Borough of Hove. Fifth Edition, Enlarged. 
Royal 8vo, 226 pp., with 52 Plates, comprising over 400 Diagrams, 
cloth $3.00 

MASONRY AND STONECUTTING, 

The Principles of Masonic Projection, and their Application to Con- 
struction. By E. Dobson, M.R.I.B.A. 12mo, cloth $1.00 

MODERN LIGHTNING CONDUCTORS. 

An Illustrated Supplement to the Report of the Lightning Research 
Committee of 1905, with Notes as to the Methods of Protection, and 
Specifications. By Killingworth Hedges, M.Inst.C.E., M.I.E.E., 
Honorary Secretary to the Lightning Research Committee, Author of 
"American Street Railways." Medium 8vo, cloth 

[Just Published Net $3.00 

"The illustrations are very interesting and give one a clear idea of what 

is likely to happen when a building is struck by lightning. Mr. Hedges' 

suggestions of possible reasons why certain protected buildings were struck 



ARCHITECTURE, BUILDING, &c. 33 

are instructive. He also explains the modern methods of fitting buildings 
with lightning conductors. To the ordinary reader the book will be of in- 
terest, and to anyone who has to design a system for protecting a building 
from lightning strokes it will be helpful " — Builder. 

PLUMBING: 

A Text-Book to the Practice of the Art or Craft of the Plumber. With 
Chapters upon House Drainage and Ventilation. By Wm. Paton 
Buchan. Ninth Edition, with 512 Illustrations. Crown 8vo, cloth. 

$1.40 

HEATING BY HOT WATER, 

VENTILATION AND HOT WATER SUPPLY. 

By Walter Jones, M.I.M.E. 360 pages, with 140 Illustrations. 
Medium 8vo, cloth $£.50 

THE PRACTICAL PLASTERER: 

A Compendium of Plain and Ornamental Plaster Work. By W. Kemp. 
12mo, cloth # £Q 

CONCRETE: ITS NATURE AND USES. 

A Book for Architects, Builders, Contractors, and Clerks of Works. By 
G E Sutcliffe, A.R.I.B.A. Second Edition, Revised and Enlarged. 
396 pp., with Illustrations. 12mo, cloth. . . .[Just Published. $3.50 

PORTLAND CEMENT FOR USERS. 

By the late Henry Faija, M.Inst.C.E. Fifth Edition. Revised and 
Enlarged by D. B. Butler, A.M.Inst.C.E. 12mo, cloth $1.20 

LIMES, CEMENTS, MORTARS, CONCRETES, MASTICS, 
PLASTERING, &c. 

By G. R. Burnell, C.E. Fifteenth Edition. 12mo, cloth.. . . .60 

MEASURING AND VALUING ARTIFICERS' WORK 

(The Student's Guide to the Practice of). Containing Directions for 
taking Dimensions, Abstracting the same, and bringing the Quantities 
into Bill, with Tables of Constants for Valuation of Labour, and for the 
Calculation of Areas and Solidities. Originally edited by E. Dobson, 
Architect. With Additions by E. W. Tarn, M.A. Seventh Edition, 
Revised. 12mo, cloth $3.00 

QUANTITIES AND MEASUREMENTS, 

In Bricklayers', Masons', Plasterers', Plumbers', Painters', Paper 
hangers', Gilders', Smiths', Carpenters' and Joiners' Work. By A. C 

Beaton, Surveyor. 12mo, cloth .60 

"This book is indispensable to builders and their quantity clerks." — Eng' 
lish Mechanic. 

TECHNICAL GUIDE, MEASURER, AND ESTIMATOR. 

For Builders and Surveyors. Containing Technical Directions for Meas- 
uring Work in all the Building Trades, Complete Specifications for 
Houses, Roads, and Drains, and an Easy Method of Estimating the 
parts of a Building collectively. By A. C. Beaton. Tenth Edition. 

Waistcoat-pocket size .60 

"No builder, architect, surveyor, or valuer should be without his 
' Beaton.' " — Building News. 

COMPLETE MEASURER; 

Setting forth the Measurement of Boards, Glass, Timber, and Stone. 
By R. Horton. Sixth Edition. 12mo, cloth $1.60 

ARCHITECTURAL PERSPECTIVE. 

The whole Course and Operations of the Draughtsman in Drawing a 
Large House in Linear Perspective. Illustrated by 43 Folding Plates. 
By F. O. Ferguson, Third Edition. 8vo, boards $1,50 



34 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
PERSPECTIVE FOR BEGINNERS 

For Students and Amateurs in Architecture, Painting, &c. By G. 
Pyne. Crown 8vo, cloth # g0 

PRACTICAL RULES ON DRAWING. 

For the Builder and Young Student in Architecture. By G. Pyne. 4to 

$3.00 
THE MECHANICS OF ARCHITECTURE. 

A Treatise on Applied Mechanics, especially Adapted to the Use of 
Architects. By E. W. Tarn, M.A., Author of "The Science of Build- 
ing," &c. Second Edition, Enlarged. Illustrated with 125 Diagrams. 

12mo, cloth $3.00 

' ' The book is a very useful and helpful manual of architectural mechan- 
ics." — Builder. 

A HANDY BOOK OF VILLA ARCHITECTURE. 

Being a Series of Designs for Villa Residences in various Styles. With 
Outline Specifications and Estimates. By C. Wickes, Architect, Au- 
thor of "The Spires and Towers of England," &c. 61 Plates, 4to, half- 
morocco, gilt edges $12.00 

DECORATIVE PART OF CIVIL ARCHITECTURE. 

By Sir William Chambers, F.R.S. With Portrait, Illustrations, Notes, 
and an Examination of Grecian Architecture, by Joseph Gwilt, 
F.S.A. Revised and Edited by W. H. Leeds. 66 Plates, 4to, cloth. 

$8.40 

HINTS TO YOUNG ARCHITECTS. 

By George Wightwick, Architect, Author of "The Palace of Archi- 
tecture," &c, &c. Sixth Edition, revised and enlarged by G. Huskis- 
bon Guillaume, Architect. 12mo, cloth $1.40 

THE ARCHITECTS' GUIDE. 

Being a Text-book of Useful Information for Architects, Engineers, Sur- 
veyors, Contractors, Clerks of Works, &c. By F. Rogers. 12mo, 

$1.40 
ARCHITECTURE— ORDERS. 

The Orders and their ^Esthetic Principles. By W. H. Leeds. 12mo. 

.60 
ARCHITECTURE— STYLES. 

The History and Description of the Styles of Architecture of Various 
Countries, from the Earliest to the Present Period. By T. Talbot 
Bury, F.R.I.B.A., &c. Illustrated. 12mo, cloth # g() 

"Orders and Styles of Architecture," in One Vol $1.40 

ARCHITECTURE— DESIGN. 

The Principles of Design in Architecture, as deducible from Nature and 
exemplified in the Works of the Greek and Gothic Architects. By Edw. 
L. Garbett, Architect. 12mo, cloth $1.00 

"We know no work that we would sooner recommend to an attentive 
reader desirous to obtain clear views of the nature of architectural art. The 
book is a valuable one." — Builder. 

*#* The three preceding Works in One handsome Vol., half-bound, entitled 
"Modern Architecture," price $2.40 

ARCHITECTURAL MODELLING IN PAPER, 

The Art of. By T. A. Richardson. 12mo, cloth # g() 



SANITATION AND WATER SUPPLY. 35 

YITRUYIUS— THE ARCHITECTURE OF MARCUS 

V1TRUVIUS POLLIO. 

In Ten Books. Translated from the Latin by J. Gwilt. With 23 
Plates. 12mo, cloth $2.00 

N.B. — This is the[only Edition of Vitrtjvius procurable at a moderate price. 

GRECIAN ARCHITECTURE, 

An Inquiry into the Principles of Beauty in ; with an Historical View 
of the Rise and Progress of the Art in Greece. By the Earl of Aber- 
deen # 4Q 

*#* The two preceding Works in One handsome Volume, half-bound, entitled 
"Ancient Architecture," price $2.40 

ACOUSTICS OF PUBLIC BUILDINGS: 

The Laws of Sound as applied to the Arrangement of Buildings. By 
Professor T. Rogers Smith, F.R.I.B.A. New Edition, revised. With 
numerous Illustrations. 12mo, cloth m QQ 

LIGHT:' 

An Introduction to the Science of Optics. Designed for the Use of 
Stilaents of Architecture, Engineering, and other Applied Sciences. By 
E. W. Tarn, M.A. 12mo, cloth # 60 



SANITATION AND WATER SUPPLY. 



THE HEALTH OFFICER'S POCKET=BOOK. 

A Guide to Sanitary Practice and Law. For Medical Officers of Health, 
Sanitary Inspectors, Members of Sanitary Authorities, &c. By Edward 
F. Willoughby, M.D. (Lond.), &c. Second Edition, Revised and En- 
larged. Fcap. 8vo, leather $4.00 

THE WATER SUPPLY OF TOWNS AND THE CON- 

STRUCTION OF WATER-WORKS. 

By Professor W. K. Burton, A.M. Inst. C.E. Second Edition, Re- 
vised and Extended. Royal 8vo, cloth. (See page 12.) $9.00 

THE WATER SUPPLY OF CITIES AND TOWNS. 

By William Humber, A.M.Inst. C.E., and M.Inst.M.E. Imp. 4to, half- 
bound morocco. (See page 12.) $45.00 

WATER AND ITS PURIFICATION. 

A Handbook for the Use of Local Authorities, Sanitary Officers, and 
others interested in Water Supply. By S. Rideal, D.Sc. Lond., F.I.C. 
Second Edition, Revised, with Additions, including numerous Illustra- 
tions and Tables. 12mo, cloth $3.00 

RURAL WATER SUPPLY. 

A Practical Handbook on the Supply of Water and Construction of 
Water-works for Small Country Districts. By Allan Greenwell, 
A.M.I. C.E. , and W. T. Curry, A.M.I.C.E. Revised Edition. 12mo, 
doth $2.00 

WATER ENGINEERING. 

A Practical Treatise on the Measurement, Storage, Conveyance, ana 
Utilisation of Water for the Supply of Towns. By C. Slagg, A.M. 
Inst.CE $3.00 



36 CROSBY LOCKWOOD & SON'S CATALOGUE. 
THE PURIFICATION OF SEWAGE. 

Being a Brief Account of the Scientific Principles of Sewage Purifica- 
tion, and their Practical Application. By Sidney Barwise, M.D 
(Lond.), B.Sc, M.R.C.S., D.P.H. (Camb.), Fellow of the Sanitary In- 
stitute, Medical Officer of Health to the Derbyshire County Council. 
Second Edition, Revised and Enlarged, with an Appendix on the Analy- 
sis of Sewage and Sewage Effluents. With numerous Illustrations and 

Diagrams. Demy 8vo, cloth Net $3.50 

Summary of Contents: — Sewage: Its Nature and Composition. — 
The Chemistry or Sewage. — Varieties of Sewage and the Changes it 
Undergoes. — River Pollution and its Effects. — The Land Treatment 
of Sewage. — Precipitation, Precipitants, and Tanks. — The Liquefac- 
tion of Sewage. — Principles involved in the Oxidation of Sewage. — 
Artificial Processes of Purification. — Automatic Distributors and 
Special Filters. — Particulars of Sewerage and Sewage Disposal 
Schemes required by Local Government Board. — Useful Data.— Ap- 
pendix: The Apparatus required for Sewage Analysis. — Standard 
Solutions used in the Method of Sewage Analysis. — Tables: Esti- 
mation of Ammonia. — Nitrogen as Nitrates. — Incubator Test, Oxygen 
Absorbed. — To Convert Grains per Gallon to Parts per 100,000. 

SANITARY WORK IN SMALL TOWNS AND VILLAGES. 

By Charles Slagg, A.M. Inst. C.E. Third Edition, Enlarged. 12mo 
doth $3.00 

VENTILATION: 

A Text-Book to the Practice of the Art of Ventilating Buildings. By 
W. P. Buchan. With 170 Illustrations. 12mo, cloth $1.40 



CARPENTRY, TIMBER, ETC. 



PRACTICAL FORESTRY. 

And its Bearing on the Improvement of Estates. By Charles E. 
Curtis, F.S.I., Professor of Forestry, Field Engineering, and General 
Estate Management, at the College of Agriculture, Downton. Second 

Edition, Revised. 12mo, cloth .$1,40 

Prefatory Remarks. — Objects of Planting. — Choice of a Forester. 
— Choice of Soil and Site. — Laying Out of Land for Plantations. — 
Preparation of the Ground for Planting. — Drainage. — Planting. — 
Distances and Distribution of Trees in Plantations. — Trees and 
Ground Game. — Attention after Planting. — Thinning of Plantations. 
— Pruning of Forest Trees. — Realization. — Methods of Sale.— 
Measurement of Timber. — Measurement and Valuation of Larch's 
Plantation. — Fire Lines. — Cost of Planting. 

WOODWORKING MACHINERY. 

Its Rise, Progress, and Construction. With Hints on the Management 
of Saw Mills and the Economical Conversion of Timber. Illustrated 
with Examples of Recent Designs by leading English, French, and 
American Engineers. By M. Powis Bale, M.Inst. C.E. , M.I.Mech.E. 
Second Edition, Revised, with large Additions. 8vo, 440 pp., cloth, 

$3.50 

SAW MILLS. 

Their Arrangement and Management, and the Economical Conversion 
of Timber. By M. Powis Bale, M.Inst.C.E., M.I.Mech.E. Second 
Edition, Revised. 12mo, cloth $4.00 



CARPENTRY, TIMBER, 6»c. 37 

THE ELEMENTARY PRINCIPLES OF CARPENTRY. 

A Treatise on the Pressure and Equilibrium of Timber Framing, the 
Resistance of Timber, and the Construction of Floors, Arches, Bridges, 
Roofs, Uniting Iron and Stone with Timber, &c. To which is added 
an Essay on the Nature and Properties of Timber, &c, with Descrip- 
tions of the kinds of Wood used in Building; also numerous Tables 
of the Scantlings of Timber for different purposes, the Specific Gravi- 
ties of Materials, &c. By Thomas Tredgold, C.E. With an Appendix 
of Specimens of Various Roofs of Iron and Stone, Illustrated. Seventh 
Edition, thoroughly Revised and considerably Enlarged by E. Wynd- 
ham Tarn, MA., Author of "The Science of Building," &c. With 
61 Plates, Portrait of the Author, and several Woodcuts. In One 
large Vol., 4to, cloth $10.00 

THE CARPENTER'S GUIDE. 

Or, Book of Lines for Carpenters ; comprising all the Elementary Prin- 
ciples essential for acquiring a knowledge of Carpentry. Founded on 
the late Peter Nicholson's standard work. A New Edition, Revised 
by Arthur Ashpitel, F.S.A. Together with Practical Rules on 
Drawing, by George Pyne. With 74 Plates, 4to, cloth $7.50 

CARPENTRY AND JOINERY— 

The Elementary Principles of Carpentry. Chiefly composed from the 
Standard Work of T. Tredgold. With Additions and a Treatise on 
Joinery by E. W. Tarn, M.A. Eighth Edition. 12mo, cloth. $1.40 

Atlas of 35 Plates to accompany and illustrate the foregoing book. 

With Descriptive Letterpress. 4to $2.40 

ROOF CARPENTRY: 

Practical Lessons in the Framing of Wood Roofs. For the use of 
Working Carpenters. By Geo. Collings. 12mo, cloth # 80 

CIRCULAR WORK IN CARPENTRY AND JOINERY. 

A practical Treatise on Circular Work of Single and Double Curvature. 
By George Collings. Fourth Edition. 12mo, cloth $1.00 

HANDRAILINQ COMPLETE IN EIGHT LESSONS. 

On the Square-Cut System. By J. S. Goldthorp, Teacher of Geometry 
and Building Construction at the Halifax Mechanics' Institute. With 
Eight Plates and over 150 Practical Exercises. 4to, cloth. . . .$1.40 

PRACTICAL TREATISE ON HANDRAILING: 

Showing New and Simple Methods. By Geo. Collings. Third Edi- 
tion, including a Treatise on Stairbuilding. 12mo, cloth $1.00 

THE CABINET-MAKER'S GUIDE TO THE ENTIRE 
CONSTRUCTION OF CABINET WORK. 

By Richard Bitmead. Illustrated with Plans, Sections and Working 
Drawings. 12mo, cloth $1.00 

THE JOINTS MADE AND USED BY BUILDERS. 

By W. J. Christy. With 160 Woodcuts. 12mo, cloth. . .- $1.20 

TIMBER IMPORTER'S, TIMBER MERCHANT'S, AND 
BUILDER'S STANDARD GUIDE. 

By R. E. Grandy. 12mo, cloth .80 

TIMBER MERCHANT'S and BUILDER'S COMPANION. 

Containing New and Copious Tables of the Reduced Weight and 
Measurement of Deals and Battens of all sizes and other Useful Tables 
for the use of Timber Merchants and Builders. By William Dowsing. 
Fifth Edition, Revised and Corrected. 12mo, cloth $1.20 



38 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
THE PRACTICAL TIMBER MERCHANT. 

Being a Guide for the Use of Building Contractors, Surveyors, Builders, 
&c, comprising useful Tables for all purposes connected with the 
Timber Trade, Marks of Wood, Essay on the Strength of Timber, 
Remarks on the Growth of Timber, &c. By W. Richardson. Second 
Edition. Fcap. 8vo, cloth $1.40 

PACKING=CASE TABLES. 

Showing the number of Superficial Feet in Boxes or Packing-Cases, 
from six inches square and upwards. By W. Richardson, Timber 
Broker. Fourth Edition. Oblong 4to, cloth $1.40 

GUIDE TO SUPERFICIAL MEASUREMENT. 

Tables calculated from 1 to 200 inches in length, by 1 to 108 inches in 
breadth. For the use of Architects, Surveyors, Engineers, Timber 
Merchants, Builders, &c. By J. Hawkings. Fifth Edition. 12mo, 
doth ■" $1.40 



DECORATIVE ARTS, ETC. 



SCHOOL OF PAINTING FOR THE IMITATION OF 
WOODS AND MARBLES. 

As Taught and Practised by A. R. Van der Burg and P. Van der 
Burg, Directors of the Rotterdam Painting Institutions. Royal folio, 
18£ by 12£ in., Illustrated with 24 full-size Coloured Plates; also 12 
plain Plates, comprising 154 Figures. Fourth Edition, cloth. 

Net $10.00 
List of Plates. 
1. Various Tools Required for Wood Painting. — 2,3. Walnut: Pre- 
liminary Stages of Graining and Finished Specimen. — 4. Tools Used 
for Marble Painting and Method of Manipulation. — 5, 6. St. Remi 
Marble; Earlier Operations and Finished Specimen. — 7. Methods of 
Sketching Different Grains, Knots, &c. — 8, 9. Ash: Preliminary 
Stages and Finished Specimen. — 10. Methods of Sketching Marble 
Grains. — 11,12. Breche Marble; Preliminary Stages of Working and 
Finished Specimen. — 13. Maple; Methods of Producing the Different 
Grains. — 14,15. Bird's-Eye Maple ; Preliminary Stages and Finished 
Specimen. — 16. Methods of Sketching the Different Species of White 
Marble. — 17, 18. White Marble; Preliminary Stages of Process and 
Finished Specimen. — 19. Mahogany; Specimens of Various Grains and 
Methods of Manipulation. — 20. 21, Mahogany; Earlier Stages and 
Finished Specimen. — 22, 23, 24. Sienna Marble; Varieties of Grain, 
Preliminary Stages and Finished Specimen. — 25, 26, 27. Juniper Wood ; 
Methods of Producing Grain, &c. ; Preliminary Stages and Finished 
Specimen. — 28, 29, 30. Vert de Mer Marble; Varieties of Grain and 
Methods of Working, Unfinished and Finished Specimens. — 31, 32, 33. 
Oak; Varieties of Grain, Tools Employed and Methods of Manipu- 
lation, Preliminary Stages and Finished Specimen. — 34, 35, 36. Waul- 
sort Marble ; Varieties of Grain, Unfinished and Finished Specimens. 

ELEMENTARY DECORATION: 

As Applied to Dwelling-Houses, &c. By J. W. Facey. 12mo, cloth. 

80 

PRACTICAL HOUSE DECORATION. 

A Guide to the Art of Ornamental Painting, the arrangement of Colours 
in Apartments, and the Principles of Decorative Design. By James W. 

Facey. 12mo, cloth $1.00 

*** The last two works in One handsome Vol., half-bound, entitled "llouss 
Decoration, Elementary and Practical," price $3.00 



DECORATIVE ARTS, &c. 39 

ORNAMENTAL ALPHABETS, ANCIENT & MEDI/EVAL. 

PYom the Eighth Century with Numerals; including Gothic. Church- 
Text, large and small, German, Italian, Arabesque, Initials for Illum- 
ination, Monograms, Crosses, &c, for the use of Architectural and En- 
gineering Draughtsmen, Missal Painters, Masons, Decorative Painters, 
Lithographers, Engravers, Carvers, &c, &c. Collected and Engraved 
by F. Delamotte, and printed in Colours. New and Cheaper Edition. 
Royal 8vo, oblong, ornamental boards $1.00 

MODERN ALPHABETS, PLAIN AND ORNAMENTAL. 

Including German, Old English, Saxon, Italic, Perspective, Greek, 
Hebrew, Court Hand Engrossing, Tuscan, Riband, Gothic, Rustic, and 
Arabesque ; with several Original Designs, and an Analysis of the Roman 
and Old English Alphabets, large and small, and Numerals, for the use 
of Draughtsmen, Surveyors, Masons, Decorative Painters, Lithog- 
raphers, Engravers, Carvers, &c. Collected and Engraved by F. Dela- 
motte, and printed in Colours. New and Cheaper Edition. Royal 8 vo, 
oblong, ornamental boards $1.00 

MEDI/EVAL ALPHABETS AND INITIALS. 

By^F. G. Delamotte. Containing 21 Plates and Illuminated Title 
printed in Gold and Colours. With an Introduction by J. Willis 
Brooks. Fifth Edition. Small 4to, ornamental boards $2.00 

A PRIMER OF THE ART OF ILLUMINATION. 

For the Use of Beginners; with a Rudimentary Treatise on the Art, 
Practical Directions for its Exercise, and Examples taken from Illumi- 
nated MSS., printed in Gold and Colours. By F. Delamotte. New 
and Cheaper Edition. Small 4to, ornamental boards $2.40 

THE EMBROIDERER'S BOOK OF DESIGN. 

Containing Initials, Emblems, Cyphers, Monograms, Ornamental Bor- 
ders, Ecclesiastical Devices, Mediaeval and Modern Alphabets, and 
National Emblems. Collected by F. Delamotte, and printed in 
Colours. Oblong royal 8vo, ornamental wrapper $1.00 

MARBLE DECORATION 

And the Terminology of British and Foreign Marbles. A Handbook 
for Students. By George H. Blagrove, Author of "Shoring and its 
Application," &c. With 28 Illustrations. 12mo, cloth $1.40 

THE DECORATOR'S ASSISTANT. 

A Modern Guide for Decorative Artists and Amateurs, Painters, Writers, 
Gilders, &c. Containing upwards of 600 Receipts, Rules, and Instruc- 
tions ; with a variety of Information for General Work connected with 
every Class of Interior and Exterior Decorations, &c. Eight Edition 
12mo .40 

GRAMMAR OF COLOURING. 

Applied to Decorative Painting and the Arts. By G. Field. New 
Edition, enlarged by E. A. Davidson. With Coloured Plates. 12mo, 
cloth. . . $1.20 

HOUSE PAINTING, GRAINING, MARBLING, AND 

SIGN WRITING. 

With a Course of Elementary Drawing, and a Collection of Useful 
Receipts. By E. A. Davidson. Ninth Edition. Coloured Plates. 
12mo, cloth $2.00 

ART OF LETTER PAINTING MADE EASY. 

By J. G. Badenoch. With 12 full-page Engravings of Examples. 12mo, 

.60 



40 CROSBY LOCKWOOD & SON'S CATALOGUE. 
PAINTING POPULARLY EXPLAINED. 

By Thomas John Gullick, Painter, and John Timbs, F.S.A. Includ- 
ing Fresco, Oil, Mosaic, Water Colour, Water-Glass, Tempera, En- 
caustic, Miniature, Painting on Ivory, Vellum, Pottery, Enamel, Glass, 

&c. Sixth Edition. 12mo, cloth $2.00 

*** Adopted as a Prize Book at South Kensington. 

GLASS STAINING, AND PAINTING ON GLASS. 

From the German of Dr. Gessert and Emanttel Otto Fromberg. 
With an Appendix on The Art of Enamelling. 12mo, cloth. .$1.00 

WOOD=CARVING FOR AMATEURS. 

With Hints on Design. By A Lady. With 10 Plates. New and 
Cheaper Edition. 12mo, in emblematic wrapper .£0 



NATURAL SCIENCE, ETC. 



THE VISIBLE UNIVERSE. 

Chapters on the Origin and Construction of the Heavens. By J. E. 
Gore, F.R.A.S., Author of "Star Groups," &c. Illustrated by 6 
Stellar Photographs asd 12 Plates. Demy 8vo, cloth, $3.75 

STAR GROUPS. 

A Student's Guide to the Constellations. By J. Ellard Gore, F.R.A.S. 
M.R.I. A., &c, Author of "The Visible Universe," "The Scenery of the 
Heavens," &c. With 30 Maps. Small 4to, cloth $2.00 

AN ASTRONOMICAL GLOSSARY. 

Or, Dictionary of Terms used in Astronomy. With Tables of Data and 
Lists of Remarkable and Interesting Celestial Objects. By J. Ellard 
Gore, F.R.A.S. 12mo, cloth $1.00 

ASTRONOMY. 

By the late Rev. R. Main, M.A., F.R.S. Third Edition, revised by 
William Thynne Lynn, B.A., F.R.A.S. 12mo, cloth .80 

THE MICROSCOPE. 

Its Construction and Management. Including Technique, Photo-micro- 
graphy, and the Past and Future of the Microscope. By Dr. Henri 
van Heurck, Re-Edited and Augumented from the Fourth French 
Edition, and Translated by Wynne E. Baxter, F.G.S. Imp. 8vo, 
cloth $7.00 

MANUAL OF THE MOLLUSCA : 

A Treatise on Recent and Fossil Shells. By Dr. S. P. Woodward, 
A.L.S. With Appendix by Ralph Tate, A.L.S., F.G.S. With 
numerous Plates and 300 Woodcuts. 12mo, cloth, $3.00 

THE TWIN RECORDS OF CREATION. 

Or, Geology and Genesis, their Perfect Harmony and Wonderful Con- 
cord. By G. W. V. le Vaux. 8vo, cloth $2.00 

LARDNER'S HANDBOOKS OF SCIENCE. 
HANDBOOK OF MECHANICS. 

Enlarged and re-written by B. Loewy, F.R.A.S, 8vo, cloth • -$2,40 



CHEMICAL MANUFACTURES, CHEMISTRY, &c. 41 

LARDNER'S HANDBOOKS OF SCIENCE— Continued. 

HANDBOOK OF HYDROSTATICS AND PNEU- 
MATICS. 

Revised and Enlarged by B. Loewy, F.R.A.S. Post 8vo, cloth, $2.00 

HANDBOOK OF HEAT. 

Edited and re-written by B. Loewy, F.R.A.S. Post 8vo, cloth, $2.40 

HANDBOOK OF OPTICS. 

New Edition. Edited by T. Olver Harding, B.A. Small 8vo, 

cloth $2.00 

ELECTRICITY, MAGNETISM, AND ACOUSTICS. 

Edited by Geo. C. Foster, B.A. Small 8vo, cloth $2.00 

HANDBOOK OF ASTRONOMY. 

Revised and Edited by Edwin Dunkin, F.R.A.S. 8vo, cloth, $3.80 

MUSEUM OF SCIENCE AND ART. 

With upwards of 1,200 Engravings. In Six Double Vols, cloth, $7.50 
Half -morocco $12.60 

NATURAL PHILOSOPHY FOR SCHOOLS.. ..$1.40 

ANIMAL PHYSIOLOGY FOR SCHOOLS $1.40 

THE ELECTRIC TELEGRAPH. 

Revised by E. B. Bright, F.R.A.S. Fcap. 8vo, cloth $1.00 



CHEMICAL MANUFACTURES, 
CHEMISTRY, ETC. 



THE OIL FIELDS OF RUSSIA AND THE RUSSIAN 
PETROLEUM INDUSTRY. 

A Practical Handbook on the Exploration, Exploitation, and Manage- 
ment of Russian Oil Properties, including Notes on the Origin of 
Petroleum in Russia, a Description of the Theory and Practice of 
Liquid Fuel, and a Translation of the Rules and Regulations concern- 
ing Russian Oil Properties. By A. Beeby Thompson, A.M.I.M.E., 
late Chief Engineer and Manager of the European Petroleum Company's 
Russian Oil Properties. About 500 pp., with numerous Illustrations 
and Photographic Plates, and a Map of the Balakhany-Saboontchy- 
Romany Oil Field. Super-royal 8vo, cloth Net $7.50 

THE ANALYSIS OF OILS AND ALLIED SUBSTANCES. 

By A. C. Wright, M.A.Oxon., B.Sc, Lond., formerly Assistant Lecturer 
in Chemistry at the Yorkshire College, Leeds, and Lecturer in Chemis- 
try at the Hull Technical School. Demy 8vo, cloth $3.50 

A HANDYBOOK FOR BREWERS. 

Being a Practical Guide to the Art of Brewing and Malting. Embracing 
the Conclusions of Modern Research which bear upon the Practice of 
Brewing. By Herbert Edwards Wright, M.A. Third Edition, 
Enlarged. 530 pp. 12mo, cloth In press 

A P0CKET=B00K OF MENSURATION AND GAUGING. 

Containing Tables, Rules, and Memoranda for Revenue Officers, 
Brewers, Spirit Merchants, &c. By J. B. Mant, Inland Revenue. 
Second Edition, Revised. 18mo, leather $1.60 



42 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
THE GAS ENGINEER'S POCKET=BOOK. 

Comprising Tables, Notes and Memoranda relating to the Manufacture. 
Distribution and Use of Coal Gas and the Construction of Gas Works. 
By H. O'Connor, A.M. Inst.C.E. Second Edition, Revised. 470 pp., 
12mo. fully Illustrated, leather $3.50 

LIGHTING BY ACETYLENE 

Generators, Burners, and Electric Furnaces. By William E. Gibbs, 
M.E. With 66 Illustrations. 12mo, cloth. , $1.50 

ENGINEERING CHEMISTRY. 

A Practical Treatise for the Use of Analytical Chemists, Engineers, 
Iron Masters, Iron Founders, Students and others. Comprising 
Methods of Analysis and Valuation of the Principal Materials used in 
Engineering Work, with numerous Analyses, Examples and Suggestions, 
By H. Joshua Phillips, F.I.C., F.C.S. Third Edition, Revised and 
Enlarged. 12mo, 420 pp., withJPlates and Illustrations, cloth, $4.50 

NITRO=EXPLOSIVES. 

A Practical Treatise concerning the Properties, Manufacture, and 
Analysis of Nitrated Substances, including the Fulminates, Smokeless 
Powders, and Celluloid. By P. Gerald Sanford, F.I.C., Consulting 
Chemist to the Cotton Powder Company, Limited, &c. With Illustra- 
tions. 12mo, cloth $3.00 

A HANDBOOK OF MODERN EXPLOSIVES. 

A Practical Treatise on the Manufacture and Use of Dynamite, Gun- 
Cotton, Nitro-Glycerine and other Explosive Compounds, including 
Collodion-Cotton. With Chapters on Explosives in Practical Applica- 
tion. By M. Eissler, M.E. Second Edition, Enlarged. 12mo, cloth, 

$5.00 

DANGEROUS GOODS. 

Their Sources and Properties, Modes of Storage and Transport. With 
Notes and Comments on Accidents arising therefrom. A Guide for 
the Use of Government and Railway Officials, Steamship Owners, &c. 
By H. Joshua Phillips, F.I.C., F.C.S. 12mo, 374 pp. ; cloth, $3.50 

"Merits a wide circulation, and an intelligent, appreciative study." — 
Chemical News. 

A MANUAL OF THE ALKALI TRADE. 

Including the Manufacture of Sulphuric Acid, Sulphate of Soda, and 
Bleaching Powder. By John Lomas, Alkali Manufacturer. With 
232 Illustrations and Working Drawings. Second Edition, with 
Additions. Super-royal, 8vo, cloth $10.00 

THE BLOWPIPE IN CHEMISTRY, MINERALOGY, Etc. 

Containing all known Methods of Anhydrous Analysis, many Working 
Examples, and Instructions for Making Apparatus. By Lieut. -Colonel 
W. A. Ross, R.A., F.G.S. Second Ed., Enlarged. Ll2mo, cloth, $2.00 

THE MANUAL OF COLOURS AND DYE=WARES. 

Their Properties, Applications, Valuations, Impurities and Sophistica- 
tions. For the Use of Dyers, Printers, Drysalters, Brokers, &c. By 
J. W. Slater. Second Edition, Revised and greatly Enlarged. 12mo, 

cloth $3.00 

" There is no other work which covers precisely the same ground. To 

students preparing for examinations in dyeing and printing it will prove 

exceedingly useful." — Chemical News. 



INDUSTRIAL AND USEFUL ARTS. 43 

THE ARTISTS' MANUAL OF PIGMENTS. 

Showing their Composition, Conditions of Permanency, Non-Per- 
manency, and Adulterations, &c, with Tests of Purity. By H. C. 

Standage. Third Edition. 12mo, cloth $1.00 

" This work is indeed multum-in-parvo, and we can, with good conscience, 

recommend it to all who come in contact with pigments, whether as makers, 

dealers, or users. ,; — Chemical Review. 



INDUSTRIAL ARTS, TRADES, AND 
MANUFACTURES. 



THE CULTIVATION AND PREPARATION OF PARA 

RUBBER. 

By W. H. Johnson, F.L.S., F.R.H.S., Director of Agriculture, Gold 
Coast Colony, West Africa, Commissioned by Government in 1902 to 
visit Ceylon to Study the Methods employed there in the Cultivation 
and Preparation of Para Rubber and other Agricultural Staples for 
Market, with a view to Introduce them into West Africa. Demy 8vo, 

doth $3.00 

Summary op Contents: — Introductory. — The Para Rubber Tree 
(Hevea brasiliensis) at Home and Abroad. — Cultivation of the Tree: — - 
Propagation. — Site for Plantation. — Distance Apart to Plant 
the Trees. — Transplanting. — Cultivation. — Insect Pests and 
Fungoid Diseases. — Collecting the Rubber: — Various Methods 
Employed in Tapping Rubber Trees. — Flow of Latex Increased by 
Wounding the Tree. — How to Tap. — The Preparation of Rubber 
from the Latex: — Latex. — Various Methods Employed in the Prep- 
aration of Rubber. — Suggested Method for Preparing Rubber. — 
Scrap Rubber. — Yield of Para Rubber from Cultivated Trees: — 
Ceylon. — Malay Peninsula. — Gold Coast, West Africa. — Establish- 
ment and Maintenance of a Para Rubber Plantation: — Ceylon. — 
Malay Peninsula. — Commercial Value of the Oil in Hevea Seeds. 

RUBBER HAND STAMPS 

And the Manipulation of Rubber. A Practical Treatise on the Manu- 
facture of India-rubber Hand Stamps, Small Articles of India-rubber, 
The Hektograph, Special Inks, Cements, and Allied Subjects. By 
T. O'Conor Sloane, A.M., Ph.D. With numerous llllustrations. 
Square 8vo, cloth $1.00 

PRACTICAL PAPER=MAKINQ. 

A Manual for Paper-Makers and Owners and Managers of Paper-Mills. 
With Tables, Calculations, &c. By G. Clapperton, Paper-Maker. 
With Illustrations of Fibres from Micro-Photographs. 12mo, cloth, 

$2.00 
THE ART OF PAPER=MAKING. 

A Practical Handbook of the Manufacture of Paper from Rags, Esparto, 
Straw, and other Fibrous Materials. Including the Manufacture of 
Pulp from Wood Fibre, with a Description of the Machinery and 
Appliances used. To which are added Details of Processes for Recover- 
ing Soda from Waste Liquors. By Alexander Watt. With Illus- 
trations. 12mo, cloth $3.00 

A TREATISE ON PAPER. 

For Printers and Stationers. With an Outline of Paper Manufacture ; 
Complete Tables of Sizes, and Specimens of Different Kinds of Paper. 
By Richard Parkinson, late of the Manchester Technical School. 
Demy 8vo, cloth $1.40 



44 CROSBY LOCKWOOD & SON'S CATALOGUE. 
THE ART OF SOAP=MAKING. 

A Practical Handbook of the Manufacture of Hard and Soft Soaps, 
Toilet Soaps, &c. Including many new Processes, and a Chapter on 
the Recovery of Glycerine from Waste Leys. By Alexander Watt. 
Sixth Edition, including an Appendix on Modern Candlemaking. 

12mo, cloth $3.00 

"A thoroughly practical treatise. We congratulate the author on the 

success of his endeavour to fill a void in English technical literature." — 

Nature. 

"The work will prove very useful, not merely to the technological student, 
but to the practical soap boiler who wishes to understand the theory of his 
art." — Chemical News. 

THE ART OF LEATHER MANUFACTURE. 

A Practical Handbook, in which the Operations of Tanning, Currying, 
and Leather Dressing are fully Described, and the Principles of Tanning 
Explained. Together with a Description of the Arts of Glue Boiling, 
Gut Dressing, &c. By Alexander Watt. Fifth Edition, thoroughly 
Revised and Enlarged. 8vo, cloth Nearly ready, $4.00 

ART OF BOOT AND SHOEMAKING, 

Including Measurement, Last-fitting, Cutting-out, Closing, and Making; 
with a Description of the most Approved Machinery employed. By 

J. B. Leno. 12mo, cloth .80 

"By far the best work ever written on the subject." — Scottish Leather 
Trader. 

COTTON MANUFACTURE. 

A Manual of Practical Instruction of the Processes of Opening, Carding, 
Combing, Drawing, Doubling and Spinning of Cotton, the Methods of 
Dyeing, &c. For the use of Operatives, Overlookers, and Manu- 
facturers. By John Lister, Technical Instructor, Pendleton. 8vo, 
cloth, $3.00 

"A distinct advance in the literature of cotton manufacture." — Machinery 
"It is thoroughly reliable, fulfilling nearly all the requirements desired." 
Glasgow Herald. 

WATCH REPAIRING, CLEANING, AND ADJUSTING. 

A Practical Handbook dealing with the Materials and Tools Used and 
the Methods of Repairing, Cleaning, Altering, and Adjusting all kinds 
of English and Foreign Watches, Repeaters, Chronographs, and Marine 
Chronometers. By F. J. Garrard, Springer and Adjuster of Marine 
Chronometers and Deck Watches for the Admiralty. With over 200 
Illustrations. 12mo, cloth $2 # Q0 

MODERN HOROLOGY, IN THEORY AND PRACTICE. 

Translated from the French of Clattditts Saunier, ex-Director of the 
School of Horology at Macon, by Jtjlien Tripplin, F.R.A.S., Besancon 
Watch Manufacturer, and Edward Rigg, M.A., Assayer in the Royal 
Mint. With Seventy-eight Woodcuts and Twenty-two Coloured 
CopperPlates. Second Edition. Super-royal, 8vo, cloth. .. -$15.00 
Half-calf $18.00 

THE WATCHMAKER'S HANDBOOK. 

Intended as a Workshop Companion for those engaged in Watchmaking 
and the Allied Mechanical Arts. Translated from the French of 
Clatjditjs Satjnier, and enlarged by Jtjlien Tripplin, F.R.A.S., and 
Edward Rigg, M.A., Assayer in the Royal Mint. Fourth Edition 
12mo, cloth $3.00 



INDUSTRIAL AND USEFUL ARTS. 45 

CLOCKS, WATCHES, & BELLS for PUBLIC PURPOSES. 

A Rudimentary Treatise. By Edmund Beckett, Lord Grimthorpe, 
LL.D., K.C., F.R.A.S. Eighth Edition, with new List of Great Bells 
and an Appendix on Weathercocks. 12mo, cloth $1.80 

HISTORY OF WATCHES & OTHER TIMEKEEPERS. 

By James F. Kendal, M. B.H.Inst. .60 boards; or cloth, gilt, $1.00 

ELECTRO-PLATING & ELECTRO=REFINING of METALS. 

Being a new edition of Alexander Watt's "Electro-Deposition." 
Revised and Largely Rewritten by Arnold Philip, B.Sc, A.I.E.E., 
Principal Assistant to the Admiralty Chemist. 8vo, cloth. . . .$4.50 

ELECTROPLATING. 

A Practical Handbook on the Deposition of Copper, Silver, Nickel, Gold, 
Aluminium, Brass, Platinum, &c, &c. By J. W. Urquhart, C.E. 
Fifth Edition, Revised. 12mo, cloth $2.00 

ELECTJRO=METALLURGY, 

Practically Treated. By Alexander Watt. Tenth Edition, enlarged 
and revised. With Additional Illustrations, and including the most 
Recent Processes. 12mo, cloth $1.40 

GOLDSMITH'S HANDBOOK, 

Containing full Instructions in the Art of Alloying, Melting, Reducing, 
Colouring, Collecting, and Refining. The Processes of Manipulation, 
Recovery of Waste, Chemical and Physical Properties of Gold; Solders, 
Enamels, and other useful Rules and Recipes, &c. By George E. 
Gee. Sixth Edition. 12mo, cloth $1.20 

SILVERSMITH'S HANDBOOK, 

On the same plan as the above. By George E. Gee. Third Edition. 

12mo, cloth $1.20 

*** The two preceding Works, in One handsome Volume, half-bound, en- 
titled "The Goldsmith's and Silversmith's Complete Handbook," $2.80 

JEWELLER'S ASSISTANT IN WORKING IN GOLD. 

A Practical Treatise for Masters and Workmen, Compiled from the 
Experience of Thirty Years' Workshop Practice. By George E. Gee. 
12mo $3.00 

HALL=MARKING OF JEWELLERY. 

Comprising an account of all the different Assay Towns of the United 
Kingdom, with the Stamps at present employed ; also the Laws relating 
to the Standards and Hall-marks at the Various Assay Offices. By 
George E. Gee. 12mo, cloth $1.20 

ELECTROTYPING. 

The Reproduction and Multiplication of Printing Surfaces and Works 
of Art by the Electro-Deposition of Metals. By J. W. Urquhart, C.E. 
12mo, cloth $2.00 

MECHANICAL DENTISTRY: 

A Practical Treatise on the Construction of the Various Kinds of 
Artificial Dentures, comprising also Useful Formula?, Tables and 
Receipts. By C. Hunter. 12mo, cloth $1.20 

BRASS FOUNDER'S MANUAL: 

Instructions for Modelling, Pattern Making, Moulding, Turning, &c. 
By W. Graham. 12mo, cloth ,80 



46 CROSBY LOCKWOOD &> SON'S CATALOGUE 
SHEET METAL WORKER'S INSTRUCTOR. 

Comprising a Selection of Geometrical Problems and Practical Rules 
for Describing the Various Patterns Required by Zinc, Sheet-Iron, 
Copper, and Tin-Plate Workers. By Reuben Henry Warn. Piactical 
Tin-Plate Worker. New Edition, Revised and greatly Enlarged by 
Joseph G. Horner, A.M.I.M.E. 12mo, 254 pp.. with 430 Illustra- 
tions, cloth S3. 00 

SHEET METAL-WORKER'S GUIDE. 

A Practical Handbook for Tinsmiths, Coppersmiths, Zincworkers, &c , 
with 46 Diagrams and Working Patterns. By W. J, E. Crane. Fourth 
Edition. 12mo, cloth # gQ 

GAS FITTING: 

A Practical Handbook. By John Black. Revised Edition With 
130 Illustrations. 12mo, cloth $1.00 

" It is written in a simple, practical style, and we heartily recommend it." 
— Plumber and Decorator. 

TEA MACHINERY AND TEA FACTORIES. 

A Descriptive Treatise on the Mechanical Appliances required in the 
Cultivation of the Tea Plant and the Preparation of Tea for the Market. 
By A. J. Wallis-Tayler, A.M.Inst.C.E. Medium 8vo, 468 pp. With 
218 Illustrations $10.00 

Summary op Contents. 

Mechanical Cultivation or Tillage or the Soil. — Plucking or 
Gathering the Leaf. — Tea Factories. — The Dressing, Manufacture, 
or Preparation of Tea by Mechanical Means. — Artificial Wither- 
ing of the Leaf. — Machines for Rolling or Curling the Leaf. — Fer- 
menting Process. — Machines for the Automatic Drying or Firing 

of the leaf. machines for non-automatic drying or flring of the 

Leaf. — Drying or Firing Machines. — Breaking or Cutting, and Sort- 
ing Machines. — Packing the Tea. — Means of Transport on Tea Plan- 
tations. — Miscellaneous Machinery and Apparatus. — Final Treat- 
ment of the Tea. — Tables and Memoranda. 

FLOUR MANUFACTURE. 

A Treatise on Milling Science and Practice, By Friedrich Kick, 
Imperial Regierungsrath, Professor of Mechanical Technology in the 
Imperial German Polytechnic Institute, Prague. Translated from the 
Second Enlarged and Revised Edition. By H. H. P. Powles, A.M. 
Inst.C.E. 400 pp., with 28 Folding Plates, and 167 Woodcuts. Royal 
8vo, cloth $10.00 

ORNAMENTAL CONFECTIONERY. 

A Guide for Bakers, Confectioners and Pastrycooks; including a 
variety of Modern Recipes, and Remarks on Decorative and Coloured 
Work. With 129 Original Designs. By Robert Wells. 12mo, cloth, 

$2.00 

BREAD & BISCUIT BAKER'S & SUGAR=BOILER'S 

ASSISTANT. 

Including a large variety of Modern Recipes. With Remarks on the 
Art of Bread-making. By Robert Wells. Fourth Edition. 12mo, 
cloth .50 

PASTRYCOOK & CONFECTIONER'S GUIDE. 

For Hotels, Restaurants, and the Trade in general, adapted also for 
Family Use. By R. Wells, Author of "The Bread and Biscuit Baker." 

.40 



INDUSTRIAL AND USEFUL ARTS. 47 

MODERN FLOUR CONFECTIONER. 

Containing a large Collection of Recipes for Cheap Cakes, Biscuits, &c. 
With remarks on the Ingredients Used in their Manufacture. By R. 
Wells .40 

SAVOURIES AND SWEETS 

Suitable for Luncheons and Dinners. By Miss M. L. Allen (Mrs. A. 
■Macaire), Author of "Breakfast Dishes," &c. Thirtieth Edition. F'cap 
8vo, sewed .40 

BREAKFAST DISHES 

For Every Morning of Three Months. By Miss Allen (Mrs. A. 
Macaire), Author of "Savouries and Sweets," &c. Twenty-second 
Edition. F'cap 8vo, sewed .40 

MOTOR CARS OR POWER CARRIAGES FOR COMMON 
ROADS. 

By A. J. Wallis-Tayler, A.M.Inst.C.E. 12mo, cloth $1.80 

FRENCH POLISHING AND ENAMELLING. 

A Practical Book of Instruction, including numerous Recipes from mak- 
ing Polishes, Varnishes, Glaze Lacquers, Revivers, &c. By R. Bit- 
mead. 12mo, cloth .60 

CEMENTS, PASTES, GLUES, AND GUMS. 

A Guide to the Manufacture and Application of Agglutinants for 
Workshop, Laboratory, or Office Use. With 900 Recipes and Formulae. 
By H. C. Standage. Crown 8vo, cloth ,80 

PRACTICAL ORGAN BUILDING. 

By W. E. Dickson, M.A., Precentor of Ely Cathedral. Second Edition, 
Revised. 12mo, cloth $1.00 

COACH=BUILDING: 

A Practical Treatise, Historical and Descriptive. By. J. W. Burgess. 
12mo, cloth $1.00 

SEWING MACHINERY. 

Construction, History, Adjusting, &c. By J. W. Urquhart. 12mo, 
cloth .80 

WOOD ENGRAVING: 

A Practical and Easy Introduction to the Study of the Art. By W. N. 
Brown. 12mo, cloth .60 

LAUNDRY MANAGEMENT. 

A Handbook for Use in Private and Public Laundries. 12mo, cloth 

.80 

CONSTRUCTION OF DOOR LOCKS. 

From the Papers of A. C. Hobbs. Edited by Charles Tomlinson, 
F.R.S. With a Note upon Iron Safes by Robert Mallet. 12mo, 
cloth $1.00 



48 CROSBY LOCKWOOD & SON'S CATALOGUE. 
HANDYBOOKS FOR HANDICRAFTS. 

BY PAUL N. HASLUCK, 

Author of "Lathe Work," &c. 12mo, 144 pp., price 50c. each. 
t5P** These Handybooks have been written to supply information for Work- 
men, Students, and Amateurs in the several Handicrafts, on the actual 
Practice of the Workshop, and are intended to convey in plain language 
Technical Knowledge of the several Crafts. In describing the processes 
employed, and the manipulation of material, workshop terms are used; work- 
shop practice is fully explained; and the text is freely illustrated with drawings 
of modern tools, appliances, and processes. 



METAL TURNER'S HANDYBOOK. 

A Practical Manual for Workers at the Foot-Lathe. With 100 Illus- 
trations .50 

WOOD TURNER'S HANDYBOOK. 

A Practical Manual for Workers at the Lathe. With over 100 Illus- 
trations # 5Q 

WATCH JOBBER'S HANDYBOOK. 

A Practical Manual on Cleaning, Repairing, and Adjusting. With 
upwards of 100 Illustrations .50 

PATTERN MAKER'S HANDYBOOK. 

A Practical Manual on the Construction of Patterns for Founders. 
With upwards of 100 Illustrations .50 

MECHANIC'S WORKSHOP HANDYBOOK. 

A Practical Manual on Mechanical Manipulation, embracing Informa- 
tion on various Handicraft Processes. With Useful Notes and Mis- 
cellaneous Memoranda. Comprising about 200 Subjects .50 

MODEL ENGINEER'S HANDYBOOK. 

A Practical Manual on the Construction of Model Steam Engines. 
With upwards of 100 Illustrations .50 

CLOCK JOBBER'S HANDYBOOK. 

A Practical Manual on Cleaning, Repairing, and Adjusting. With 
upwards of 100 Illustrations .50 

CABINET WORKER'S HANDYBOOK. 

A Practical Manual on the Tools, Materials, Appliances, and Processes 
employed in Cabinet Work. With upwards of 100 Illustrations. .50 

"Mr. Hasluck's thorough-going little Handybook is amongst the most 
practical guides we have seen for beginners in cabinet-work." — Saturday 
Review. 

WOODWORKER'S HANDYBOOK. 

Embracing Information on the Tools, Materials, Appliances, and 
Processes Employed in Woodworking. With 104 Illustrations. .50 



COMMERCE, COUNTING-HOUSE WORK, &c. 49 



COMMERCE, COUNTING-HOUSE WORK, 
TABLES, ETC. 



LESSONS IN COMMERCE. 

By Professor R. Gambaro, of the Royal High Commercial School at 
Genoa. Edited and Revised by James Gault, Professor of Commerce 
and Commercial Law in King's College, London. Fifth Edition. 
12mo, cloth 51151.40 



THE BOREIQN COMMERCIAL CORRESPONDENT. 

Being Aids to Commercial Correspondence in Five Languages — English, 
French, German, Italian, and Spanish. By Conrad E. Baker. Third 
Edition, Carefully Revised Throughout. 12mo, cloth $1.80 



FACTORY ACCOUNTS: their PRINCIPLES & PRACTICE. 

A Handbook for Accountants and Manufacturers, with Appendices on 
the Nomenclature of Machine Details; the Income Tax Acts; the 
Rating of Factories ; Fire and Boiler Insurance ; the Factory and Work- 
shop Acts, &c, including also a Glossary of Terms and a large number 
of Specimen Rulings. By Emile Garckb and J. M. Fells. Fifth 
Edition, Revised and Enlarged. Demy 8vo, cloth $3.00 



MODERN METROLOGY. 

A Manual of the Metrical Units and Systems of the present Century. 
With an Appendix containing a proposed English System. By 
Lowis d'A. Jackson, A.M. Inst. C.E., Author of "Aid to Survey Prac- 
tice," &c. 8vo, cloth $5.00 



SERIES OF METRIC TABLES. 

In which the British Standard Measures and Weights are compared 
with those of the Metric System at present in Use on the Continent. 
By C. H. Dowling, C.E. 8vo, cloth $4.00 



IRON=PLATE WEIGHT TABLES. 

For Iron Shipbuilders, Engineers, and Iron Merchants Contpining the 
Calculated Weights of upwards of 150,000 different sizes of Iron Plates 
from 1 foot by 6 in. by i in. to 10 feet by 5 feet by 1 in. Worked out 
on the Basis of 40 lbs. to the square foot of Iron of 1 inch in thickness. 
By H. Burlinson and W. H. Simpson. 4to, half-bound $10.00 



5o CROSBY LOCKWOOD &> SON'S CATALOGUE. 

AGRICULTURE, FARMING, 
GARDENING, ETC. 



THE COMPLETE GRAZIER AND FARMER'S AND 
CATTLE BREEDER'S ASSISTANT. 

A Compendium of Husbandry.. Originally Written by William 
Youatt. Fourteenth Edition, entirely Re-written, considerably En- 
larged, and brought up to Present Requirements, by William Fream, 
LL.D., Assistant Commissioner, Royal Commission on Agriculture, 
Author of "The Elements of Agriculture," &c. Royal, 8vo, 1,100 pp., 
450 Illustrations, handsomely bound $1#.00 

STOCK: CATTLE, SHEEP, AND HORSES. 

Vol. III.— OUTLINES OF MODERN FARMING. By R. Scott Burn. 
Woodcuts. 12mo, cloth $1.00 

SHEEP: 

The History, Structure, Economy, and Diseases of. By W. C. Spooner. 
Fifth Edition, with Engravings, including Specimens of New and 
Improved Breeds. 12mo, cloth $1.40 

MEAT PRODUCTION: 

A Manual for Producers, Distributors, and Consumers of Butchers' 
Meat. By John Ewart. 12mo, cloth $1.00 

MILK, CHEESE, AND BUTTER. 

A Practical Handbook on their Properties and the Processes of their 
Production. Including a Chapter on Cream and the Methods of its 
Separation from Milk. By John Oliver, late Principal of the Western 
Dairy Institute, Berkeley. With Coloured Plates and 200 Illustra- 
tions. 12mo, cloth $3.00 

BRITISH DAIRYING. 

A Handy Volume on the Work of the Dairy-Farm. For the Use of 
Technical Instruction Classes, Students in Agricultural Colleges and 
the Working Dairy-Farmer. By Prof. J. P. Sheldon. With Illus- 
trations. Second Edition, Revised. 12mo, cloth $1.00 

DAIRY, PIGS, AND POULTRY. 

Vol. IV. OUTLINES OF MODERN FARMING. By R. Scott 
Burn. Woodcuts. 12mo, cloth .80 

THE ELEMENTS OF AGRICULTURAL GEOLOGY. 

A Scientific Aid to Practical Farming. By Primrose McConnell. 
Author of "Note-book of Agricultural Facts and Figures." 8vo, cloth, 

$7.50 
SOILS, MANURES, AND CROPS. 

Vol. I.— OUTLINES OF MODERN FARMING. By R. Scott Burn. 
Woodcuts. 12mo, cloth .80 

FERTILISERS AND FEEDING STUFFS. 

Their Properties and Uses. A Handbook for the Practical Farmer. 
By Bernard Dyer, D.Sc (Lond.) With the Text of the Fertilisers 
and Feeding Stuffs Act of 1893, The Regulations and Forms of the 
Board of Agriculture, and Notes on the Act by A. J. David, B.A., 
LL.M. Fourth Edition, Revised. 12mo, cloth ,40 

THE ROTHAMSTED EXPERIMENTS AND THEIR 

PRACTICAL LESSONS FOR FARMERS. 

Part I. Stock. Part II. Crops. By C. J. R. Tipper. 12mo, cloth 

$1.40 



AGRICULTURE, FARMING, GARDENING, &c. 51 
SYSTEMATIC SMALL FARMING. 

Or, The Lessons of My Farm. Being an Introduction to Modern Farm 
Practice for Small Farmers. By R. Scott Burn, Author of "Outlines 
of Modern Farming," &c. 12mo, cloth $2.40 

THE FIELDS OF GREAT BRITAIN. 

A Text-Book of Agriculture. Adapted to the Syllabus of the Science 
and Art Department. For Elementary and Advanced Students. By 
Hugh Clements (Board of Trade). Second Edition, Revised, with 
Additions. 18mo, cloth $1.00 

OUTLINES OF MODERN FARMING. 

By R. Scott Burn. Soils, Manures, and Crops — Farming and Farming 
Economy — Cattle, Sheep, and Horses — Management of Dairy, Pigs, 
and Poultry — Utilisation of Town-Sewage, Irrigation, &c. Sixth 
Edition. In One Vol., 1,250 pp., half-bound, profusely Illustrated. 

$4.80 

FARM ENGINEERING, The COMPLETE TEXT=BOOK of. 

Comprising Draining and Embanking; Irrigation and Water Supply; 
Farm Roads, Fences and Gates; Farm Buildings; Barn Implements 
and machines; Field Implements and Machines; Agricultural Survey- 
ing, &c. By Professor John Scott. 1,150 pp., half-bound, with over 
600 Illustrations $4.80 

DRAINING AND EMBANKING. 

A Practical Treatise. By John Scott, late Professor of Agriculture 
and Rural Economy at the Royal Agricultural College, Cirencester. 
With 68 Illustrations. 12mo, cloth .60 

"A valuable handbook to the engineer as well as to the surveyor." — Land. 

IRRIGATION AND WATER SUPPLY: 

A Practical Treatise on Water Meadows, Sewage Irrigation, Warping, 
&c; on the Construction of Wells, Ponds, and Reservoirs, &c. By 
Professor J. Scott. 12mo, cloth .60 

FARM ROADS, FENCES, AND GATES: 

A Practical Treatise 'on the Roads, Tramways, and Waterways of the 
Farm; the Principles of Enclosures; and on Fences, Gates, and Stiles. 
By Professor John Scott. 12mo, cloth ,60 

BARN IMPLEMENTS AND MACHINES: 

Treating of the Application of Power to the Operations of Agriculture 
and of the various Machines used in the Threshing-barn, in the Stock- 
yard, Dairy, &c. By Professor John Scott. With 123 Illustrations. 
12mo, cloth ,80 

FIELD IMPLEMENTS AND MACHINES: 

With Principles and Details of Construction and Points of Excellence, 
their Management, &c. By Professor John Scott. With 138 Illus- 
trations. 12mo, cloth 80 

AGRICULTURAL SURVEYING. 

A Treatise on Land Surveying, Levelling, and Setting-out ; with Direc- 
tions for Valuing and Reporting on Farms and Estates. By Professor 
J. Scott. 12mo, cloth .60 

OUTLINES OF FARM MANAGEMENT. 

Treating of the General Work of the Farm; Stock; Contract Work, 
Labour, &c. By R. Scott Burn. 12mo, cloth $1.00 

OUTLINES OF LANDED ESTATES MANAGEMENT. 

Treating of the Varieties of Lands, Methods of Farming, the Setting-out 
of Farms, &c; Roads, Fences, Gates, Irrigation, Drainage, &c. By 
R. S. Burn. 13mo, cloth $1.00 



52 CROSBY LOCKWOOD & SON'S CATALOGUE. 
FARMING AND FARMING ECONOMY. 

Historical and Practical. Vol. II.— OUTLINES OF MODERN 
FARMING. By R. Scott Burn. 12mo, cloth $1.20 

UTILIZATION OF SEWAGE, IRRIGATION, &c. 

Vol. V.— OUTLINES OF MODERN FARMING. By R. Scott Burn. 
Woodcuts. 12mo, cloth $1.00 

N0TE=B00K OF AGRICULTURAL FACTS & FIGURES 
FOR FARMERS AND FARM STUDENTS. 

By Primrose McConnell, B.Sc, Fellow of the Highland and Agri- 
cultural Society, Author of "Elements of Farming." Seventh Edition, 
Re-written, Revised, and greatly Enlarged. Fcap. 8vo, 480 pp., 
leather, gilt edges [Just Published. $3.0<l> 

TABLES and MEMORANDA for FARMERS, GRAZIERS, 
AGRICULTURAL STUDENTS, SURVEYORS, LAND AGENTS, 
AUCTIONEERS, &c. 

With a New System of Farm Book-keeping. By Sidney Francis. 
Fifth Edition. 272 pp., waistcoat-pocket size, limp leather. . . 60 

THE HAY AND STRAW MEASURER: 

New Tables for the Use of Auctioneers, Valuers, Farmers, Hay and 
Straw Dealers, &c, forming a complete Calculator and Ready Reck- 
oner. By John Steele. 12mo, cloth .go 

READY RECKONER FOR ADMEASUREMENT OF LAND. 

By A. Arman. Revised and extended by C. Norris, Surveyor. Fifth 
Edition. 12mo, cloth 80 

THE HORTICULTURAL N0TE=B00K. 

A Manual of Practical Rules, Data, and Tables, for the use of Students, 
Gardeners, Nurserymen, and others interested in Flower, Fruit, and 
Vegetable Culture, or in the Laying-out and Management of Gardens. 
By J. C. NewsHAM, F.R.H.S., Headmaster of the Hampshire County 
Council Horticultural School. With numerous Illustrations. Fcap. 
8vo, cloth [Just Published. $3.00 

MARKET AND KITCHEN GARDENING. 

By C. W. Shaw, late Editor of "Gardening Illustrated." Crown 8vo, 

$1.40 
A PLAIN GUIDE TO GOOD GARDENING; 

Or, How to Grow Vegetables, Fruits, and Flowers. By S. Wood. 
Fourth Edition, with considerable Additions, and numerous Illustra- 
tions. 12mo, cloth '. $1.40 

THE FORCING GARDEN; 

Or, How to Grow Early Fruits, Flowers and Vegetables. With Plans 
and Estimates for Building Glasshouses, Pits and Frames. With 
Illustrations. By Samuel Wood. 12mo, cloth $1.40 

KITCHEN GARDENING MADE EASY. 

Showing the best means of Cultivating every known Vegetable and 
Herb, &c, with directions for management all the year round. By 
Geo. M. F. Glennt. Illustrated. 12mo, cloth .60 

COTTAGE GARDENING; 

Or, Flowers, Fruits, and Vegetables for Small Gardens. By E. Hobday. 
12mo, cloth .60 

GARDEN RECEIPTS. 

Edited by Charles W. Quin. Fourth Edition. 12mo, cloth, .60 

MULTUM=IN=PARVO GARDENING; 

Or, How to Make One Acre of Land produce $3007 a year, by the 
Cultivation of Fruits and Vegetables; also, How to Grow Flowers in 
Three Glass Houses, so as to realise $853.60 per annum clear Profit. 
By Samuel Wood, Author of "Good Gardening," &c. Sixth Edition. 
12mo, paper .50 



AGRICULTURE, FARMING, GARDENINR, &c. 53 
THE LADIES' MULTUM=IN=PARVO FLOWER GARDEN. 

And Amateur's Complete Guide. By S.Wood. 12mo, cloth, $1.40 

FRUIT TREES, 

The Scientific and Profitable Culture of From the French of M. Dtr 
Breuil. Fifth Edition, carefully Revised by George Glenny. With 
187 Woodcuts. 12mo, cloth $1.40 

ART OF GRAFTING AND BUDDING. 

By Charles Baltet. With Illustrations. 12mo,. cloth. , . . . .$1.00 

TREE PRUNER: 

Being a Practical Manual on the Pruning of Fruit Trees, including also 
their Training and Renovation, also treating of the Pruning of Shrubs, 
Climbers, and Flowering Plants. With numerous Illustrations. By 
Samuel Wood, Author of "Good Gardening," &c. 12mo, cloth. .60 

TREE PLANTER AND PLANT PROPAGATOR: 

With numerous Illustrations of Grafting, Layering, Budding, Imple- 
ments, Houses, Pits, &c. By S. Wood. 12mo, cloth .SO 

" Sound 4n its teaching and very comprehensive in its aim. It is a good 
book." — Gardeners' Magazine. 

*** The above Two Vols, in One, handsomely half-bound, entitled "The 
Tree Planter, Propagator and Pruner." By Samuel Wood. 

$1.40 

THE CULTIVATION AND PREPARATION OF PARA 
RUBBER. 

By W. H. Johnson, F.L.S., F.R.H.S. 8vo, cloth Net $3.00 

For Summary of Contents, see page 43. 

BEES FOR PLEASURE AND PROFIT. 

A Guide to the Manipulation of Bees, the Production of Honey, and the 
General Management of the Apiary. By G. Gordon Samson. With 
numerous Illustrations. 12mo, wrapper .40 



MATHEMATICS, ARITHMETIC, ETC. 



TREATISE ON MATHEMATICS, 

As applied to the Constructive Arts. By Francis Campin, C.E., &c. 
Third Edition. 12mo, cloth $1.20 

SLIDE RULE, AND HOW TO USE IT. 

Containing full, easy, and simple Instructions to perform all Business 
Calculations with unexampled rapidity and accuracy. By Charles 
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12mo '.-.'.' $1.0J 

MATHEMATICAL TABLES, 

For Trigonometrical, Astronomical, and Nautical Calculations; to 
which is prefixed a Treatise on Logarithms. By H. Law, C.E. To- 
gether with a Series of Tables for Navigation and Nautical Astronomy. 
By Professor J. R. Young. New Edition. 12mo, cloth $1.60 

LOGARITHMS. 

With Mathematical Tables for Trigonometrical, Astronomical, and 
Nautical Calculations. By Henry Law, C.E. Revised Edition, 
(Forming part of the preceding work.) 12mo, cloth $1.20" 



54 CROSBY LOCKWOOD 6» SON'S CATALOGUE. 
EUCLID, 

The Elements of; with many Additional Propositions and Explanatory 
Notes; to which is prefixed an Introductory Essay on Logic. By 

Henry Law, C.E. 12mo, cloth $1.00 

*** Sold also separately, viz.: — 

EUCLID. The First Three Books. By Henry Law, C.E. Crown 8vo, 
cloth .60 

EUCLID. Books 4, 5, 6, 11, 12. By Henry Law, C.E. Crown 8vo, 
cloth .60 

THEORY OF COMPOUND INTEREST AND ANNUITIES, 

With Tables of Logarithms for the more Difficult Computations of 
Interest, Discount, Annuities, &c, in all their Applications and Uses 
for Mercantile and State Purposes. By Fedor Thoman, of the Societe' 
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ARITHMETIC, 

Rudimentary, for the Use of Schools and Self-Instruction. By James 
Haddon, M.A. Revised by Abraham Arman. 12mo, cloth.. .60 

ARITHMETIC, 

A Rudimentary Treatise on: with full Explanations of its Theoretical 
Principles, and numerous Examples for Practice. For the use of 
Schools and for Self -Instruction. By J. R. Young, late Professor of 
Mathematics in Belfast College. 14th Ed. 12mo, cloth .... .60 

KEY TO THE ABOVE. 

By J. R. Young. 12mo, cloth .60 

EQUATIONAL ARITHMETIC, 

Applied to Questions of Interest, Annuities, Life Assurance , and General 
Commerce: with various Tables by which all calculations may be 
greatly facilitated. By W. Hipsley. 12mo, cloth 60 

COMMERCIAL BOOK-KEEPING. 

With Commercial Phrases and Forms in English, French, Italian, and 
German. By James Haddon, M.A., formerly Mathematical Master, 
King's College School. 12mo, cloth .60 

ALGEBRA, 

The Elements of. By James Haddon, M.A., formerly Mathematical 
Master of King's College School. With Appendix, containing Mis- 
cellaneous Investigations, and a collection of Problems. 12mo, cloth, 

.80 

KEY AND COMPANION TO THE ABOVE. 

An extensive repository of Solved Examples and Problems in Illustra- 
tion of the various Expedients necessary in Algebraical Operations. 
By J. R. Young. 12mo, cloth 60 

DESCRIPTIVE GEOMETRY, 

An elementary Treatise on; with a Theory of Shadows and of Per- 
spective extracted from the French of G. Monge. To which is added 
a Description of the Principles and Practice of Isometrical Projection. 
By J. F. Heather, M.A. With 14 Plates. 12mo, cloth . . .80 

PRACTICAL PLANE GEOMETRY: 

Giving the Simplest Modes of Constructing Figures contained in one 
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M.A. 12mo, cloth gQ 



MATHEMATICS, ARITHMETIC, &c. 55 

ANALTYICAL GEOMETRY AND CONIC SECTIONS. 

By J. Hann. Enlarged by Professor J. R. Young. Crown 8vo, cloth 

.80 
PLANE TRIGONOMETRY, 

The Elements of. By James Hann, M.A. Seventh Edition. 12mo, 

.60 

SPHERICAL TRIGONOMETRY, 

The Elements of. By James Hann. Revised by Charles H. Dow. 

ling, C.E. 12mo, cloth >y j , 

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8vo, cloth $1.0 J 

DIFFERENTIAL CALCULUS, 

Elements of the. By W. S. B. Woolhouse. 12mo, cloth. .. . # gQ 

INTEGRAL CALCULUS. 

By Ht)MERSHAM Cox, B.A. 12mo, cloth 4 gQ 

MATHEMATICAL INSTRUMENTS, 

A Treatise on; Their Construction, Adjustment, Testing, and Use con- 
cisely explained. By J. F. Heather, M.A., of the Royal Military 
Academy, Woolwich. Fifteenth Edition, Revised with Additions, by 
A. T. Wai.misley, M.Inst.C.E., Fellow of the Surveyors' Institution. 
Original Edition in One Vol., Illustrated. 12mo, cloth > gQ 

*** In ordering be careful to say "Original Edition," to distinguish it from the 
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DRAWING AND MEASURING INSTRUMENTS. 

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and Plans. II. Instruments used for the purposes of Accurate Measure- 
ment, and for Arithmetical Computations. By J. F. Heather M A 
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OPTICAL INSTRUMENTS. 

Including (more especially) Telescopes, Microscopes, and Apparatus for 
producing copies of Maps and Plans by Photography. By J. F. 
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SURVEYING AND ASTRONOMICAL INSTRUMENTS. 

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written. Three parts as above. 12mo, cloth $1.80 

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The Principles and Practice of ; embraoing also a clear development of 
Hydrostatics, Hydrodynamics, and Central Forces. By T. Baker, 
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3L 



56 CROSBY LOCKWOOD &■ SON'S CATALOGUE. 
LAW AND MISCELLANEOUS. 



PATENTS for INVENTIONS, HOW to PROCURE THEM. 

Compiled for the Use of Inventors, Patentees and others. By G. G. M. 
Hardingham, Assoc. Mem. Inst. C.E., &c. Demy 8vo, cloth, ,g() 

DICTIONARY OF PAINTERS, 

And Handbook for Picture Amateurs; being a Guide for Visitors to 
Public and Private Picture Galleries, and for Art Students including 
Glossary of Terms, &c. By Philippe Daryl, B.A. 12mo, cloth. {fcjl.OO 

DICTIONARY OF TERMS USED IN ARCHITECTURE. 

Building Engineering, Mining, Metallurgy, Archeology, the Fine Arts, 
&c. By John Wbale. Sixth Edition. Edited by Robt. Hunt, 
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INDEX OF SUBJECTS. 



Acetylene Gas, Gibbs, 42 

Acoustics, Smith, 35 

Aerial Navigation, Walker, 11 

Tramways, Tayler, 2 

Agricultural Geology, McCon- 
nell, 50 

Note Book, McConnell, 52 

Surveying, Scott, 5 1 

Air Machinery, Weisbach, 9, 22 
Algebra, H addon, 54 
Alkali Trade, Lomas, 42 
Alphabets, Delamotte, 39 
Alternating Current Machines, 

Sheldon and Mason, 29 
Animal Physics, Lardner, 56 

Physiology, Lardner, 41 

Arches, Piers, &c, Bland, 32 
Architect's Guide, Rogers, 34 
Architectural Modelling, Rich- 
ardson, 34 
Architecture, Ancient, 34 

Civil, Chambers, 34 

Design, Garbett, 34 

Grecian, Aberdeen, 35 

Mechanics of, Tarn, 34 

Modern, 34 

of Vitruvius, Gwilt, 35 

Orders, Leeds, 34 

Orders and Styles, 34 

Styles, Bury, 34 

Arithmetic, H addon, 54 

Young, 54 

Equational, Hipsley, 54 



Armature, Windings, Arnold, 29 
Artists' Pigments, Standage, 43 
Asbestos, Jones, 27 
Astronomical Glossary, Gore, 40 
Astronomy, Lardner, 41 
Main and Lynn, 40 

Barn Implements, Scott, 51 

Beams, Flexure of, Guy, 18 

Bees, Samson, 53 

Blasting, Burgoyne, 19 

Blowpipe, i?<m, 42 

Boiler and Factory Chimneys, 

Wilson, 4 
Boilers, Armstrong, 5 

Bauer, 20 

Courtney, 3 

Foley, 3 

Horner, 4 

Hutton, 3 

-j Wilson, 4 

Book-keeping, H addon, 54 
Boot and Shoe Making, Zerao, 44 
Brass Founding, Graham, 45 
Bread and Biscuit Baker, Wells, 
46 
Breakfast Dishes, Allen, 47 
Brewing and Malting, Wright, 

4i 
Brick and Tile Book, 33 

Making, Dobson, 32 

Brick-cutting, Hammond, 32 
Bricklaying, Hammond, 32 

57 



5» 



INDEX TO CATALOGUE. 



Brickwork, Walker, 32 
Bridges, Iron, Humber, 16 

Iron, Pendred, 16 

Oblique, Buck, 16 

Tubular, Dempsey, 17 

Bridges and Viaducts, Campin, 

17 
British Mining, Hunt, 25 
Builders' Measuring, Beaton, 33 

Quantities, Beaton, 33 

Building, a Book on, Beckett, 31 

Art of, Dobson, 31 

Construction, Allen, 31 

Cottage, Allen, 31 

Dwelling Houses, Brooks, 

3 2 

Estates, Maitland, 31 

Farm, Scott, 32 

Science of, Tarn, 31 

Cabinet-Making, Bitmead, 37 

Working, Hasluck, 48 

Calculator, O'Gorman, 56 
Calculus, Differential, Woolhouse, 

55 

Integral, Cox, 55 

Carpenter's Guide, Nicholson, 

37 
Carpentry and Joinery, Tredgold 
and Tarn, 37 

Tredgold, 37 

Cattle, Sheep, &c, Burn, 50 
Cements, &c, Standage, 47 
Chain Cables, Traill, 20 
Chemistry of Mining, Byrom, 26 
Chimneys, Wilson, 4 
Circular Work, Collings, 37 
Civil Engineering, Law, 18 
Clock Jobbing, Hasluck, 48 
Clocks, Watches, and Bells, 

Beckett, 45 
Coach-Building, Burgess, 47 
Coal & Iron Industries, Meade, 

26 

Mining, Cockin, 26 

Smyth, 26 

Colliery Manager, Pamely, 25 

■ Working, Bulman and Red- 

mayne, 26 



Colouring, .FVe/i &" Davidson, 

39 
Colours & Dye Wares, Slater, 

42 
Commerce, Gambaro, 49 
Commercial Correspondence, 

Baker, 49 
Compound Interest, Thoman, 

54 
Concrete, Sutcliffe, 33 
Confectioner, Flour, Wells, 47 
Confectionery, Wells, 46 
Constructional Ironwork, 

Campin, 17 
Copper, Metallurgy of, Eissler, 

24 
Cottage Building, Allen, 31 

Gardening, Hobday, 52 

Cotton Manufacture, Lister, 

44 
Cranes, Glynn, 11 
Creation, Records of, Le Fa«#, 

40 
Curves, Tables of, Beazeley, 15 
Cyanide Process, Eissler, 23 

Dairying, British, Sheldon, 50 
Dairy, Pigs, and Poultry, -Bwrw, 

5° 
Dangerous Goods, Phillips, 42 
Decoration, Facey, 38 
House-Painting, Graining, 

&c, 38 
Imitation of Woods and 

Marbles, 38 

Marble, Blagrove, 39 

Decorator's Assistant, 39 

Deep Level Mines of the Rand, 

Denny, 22 
Diamond Drilling, Denny, 23 
Dictionary of Architecture, 

Weale and Hunt, 56 

Painters, Daryl, 56 

Direct Current Machines, Sheldon 

and Mason, 29 
Drainage of Lands, Clark, 14 

(Mine), Michell, 25 

Draining & Embanking, Scott, 
5i 



INDEX TO CATALOGUE. 



59 



Drawing Instruments, Heather, 
55 

Rules on, Pyne, 34 

Dwelling Houses, Brooks, 32 

Dynamic Electricity, Atkinson, 

3° 

Dynamo Construction, Urquhart, 

29 

How to Make, Crofts, 29 

Motor and Switchboard 

Circuits, Bowker, 29 

Earthwork, Graham, 16 
Tables, Broadbent &• Cam- 
pin, 16 

Tables, Buck, 16 

Earthy Minerals, Davies, 24 
Electrical Calculations, Atkinson, 

3° 

■ Conductors, Perrine, 29 

Engineering, Alexander, 28 

Sewell, 28 

— — Pocket Book, Kempe, 30 

Transmission, Abbott, 28 

Electricity Applied to Mining, 
Lupton, Parr, &> Perkin, 25, 28 

Lardner and Foster, 41 

Text-Book, Noad, 30 

Electric Light Fitting, Urquhart, 

3° 

Light, Knight, 30 

Light, Urquhart, 30 

Lighting, Swinton, 30 

Ship-Lighting, Urquhart, 30 

': Telegraph, Lardner, 41 

Electro-Metallurgy, Watt, 45 

■ Plating, Urquhart, 45 

Plating, Watt and Philip, 

45 

Typing, Urquhart, 45 

Embroiderer's Design, Delamotte, 

39 
Engine-Driving Life, Reynolds, 

6 
Engineering Chemistry, Phillips, 

42 

Drawing, Maxton, 8 

Estimates, 9 

Engineering Tools, Horner, 2 



Engineer's Assistant, Templeton, 

8 

Companion, Edwards, 8 

Field Book, Haskoll, 15 

Handbook, Hutton, 5 

Pocket-Book, C/ar&, 7 

Reference Book, Foley, 3 

Turning, Horner, 2 

Year Book, Kempe, 7 

Engineman's Companion, Reyn- 
olds, 7 
Euclid, Law, 54 
Excavating, Prelim, 16 
Explosives, Eissler, 42 
Nitro, Sanjord, 42 

Factory Accounts, Garcke &■ 

Fells, 49 
Farm Buildings, ScoM, 32 

Engineering, Scott, 5 1 

Management, Burn, 5 1 

Roads, &c, Scott, 51 

Farmer's Tables, Francis, 52 
Farming Economy, Bum, 52 

Outlines, Burn, 51 

Small, Burn, 5 1 

Fertilisers, &c, Dyer, 50 
Field Fortification, Knollys, 56 

Implements, ScoW, 5 1 

Fields of Gt. Britain, Clements, 
5 1 
Fires & Fire Engines, Young, n 
Flour, Kick and Powles, 46 
Forestry, Curtis, 36 
Foundations, &c, Dobson, 19 
French Polishing, Bitmead, 47 
Fruit Trees, Du Breuil, 53 
Fuel, Williams and Clark, 10 
Fuels, Phillips, 10 

Garden, Forcing, Wood, 52 

Receipts, Quin, 52 

Gardening, Good, Wood, 52 

Ladies', Wood, 53 

Multum-in-Parvo, Wood, 

5 2 
Gas and Oil Engines, Bale, J 
Engines, Goodeve, 7 



6o 



INDEX TO CATALOGUE. 



Gas Engineer's Pocket Book, 

O'Connor, 42 

Fitting, Black, 47 

Producer Plants, Mathot, 

6 

Works, Hughes, 18 

Geology, Historical, Tate, 27 

Physical, Tate, 27 

Tate, 27 

Geometry, Tarn, 17 

Analytical, Hann, 55 

Descriptive, Heather, 54 

Technical, Sprague, 17 

■ of Compasses, Byrne, 17 

Plane, Heather, 54 

Girders (Iron), Buck, 17 

Glass Staining, Gessert and 

Fromberg, 40 
Gold Assaying, Phillips, 23 

and Silver, Merritt, 23 

Metallurgy of, Eissler, 23 

Prospecting, Rankin, 23 

Goldsmith's Handbook, Gee, 45 

and Silversmith, Gee, 46 

Grafting and Budding, Baltet, 

53 
Granites, Harris, 27 
Grazier, Complete, Fream, 50 

Hall Marking Jewellery, Gee, 

45 
Handrailing, Collin gs, 37 

Goldthorp, 37 

Hay & Straw Measurer, Steele, 

5 2 
Health Officer, Willoughby, 35 
Heat (Expansion by), Keily, 18 
Heat, Lardner and Loewy, 41 
Heating by Hot Water, Jones, 

33 
Hints to Architects, Wightwick 

andGuillaume, 34 
Hoisting Machinery, Horner, 2 
Hoisting & Conveying Ma- 
chinery, Zimmer, 2 
Horology, Saunter, 44 
Horticulture, N ewsham, 52 
House Decoration, Facey, 38 
Painting, Davidson, 39 



Hydraulic Manual, Jackson, 13 

Engineering, Marks, 13 

Tables, Neville, 13 

Hydrostatics, Lardner, 41 

Illumination, Delamotte, 39 
India Rubber, Johnson, 43, 53 
Inflammable Gas, Clowes, 26 
Iron and Steel, Hoare, 8 
Iron, Metallurgy of, Bauerman, 

25 

Ores, Kendall, 25 

Plate Weight Tables, 

Burlinson and Simpson, 49 
Irrigation, Mawson, 11 
and Water Supply, 5coW, 

5 1 

Jeweller's Assistant, Gee, 45 
Joints (Builders'), Christy, 37 

Key to Haddon's Algebra, 54 
— — to Young's Arithmetic, 54 
Kitchen Gardening, Glenny, 52 

Land, Ready Reckoner, Arman, 

5 2 

(Reclamation of), Beaze- 

ley, 12 
Landed Estates, Burn, 51 
Lathe Work, Hasluck, 9 
Laundry, Management, 47 
Lead (Argentiferous), Eissler, 

24 
Leather Manufacture, Watt, 44 
Letter Painting, Badenoch, 39 
Levelling, Simms, 15 
Light, Tarn, 35 
Light Railways, Calthrop, n 
Lightning Conductors, Hedges, 

32 
Limes, Cements, Burnett, 33 
Locks, Tomlinson, 47 
Locomotive Engine, Stretton, 6 

Engine, W eatherburn, 6 

Engine Driving, Reynolds, 6 

Engineer, Reynolds, 6 

Engines, Dempsey, 6 



INDEX TO CATALOGUE. 



61 



Logarithms, Law, 53 

Machine Shop Tools, 2 
Machinery, Details, Campin, 9 
Marble Decoration, Blagrove, 

39 

Marine Engineering, Brewer, 

20 

Engineer, Wannan, 20 

Engineer's Pocket Book, 

Wannan, 20 
Marine Engines & Boilers, 
Bauer, Donkin and Robertson, 

19 

Engines, Murray, 20 

Market Gardening, Shaw, 52 
Masonry, Purchase, 32 
and Stone-Cutting, Dob- 
son, 32 

Dams, Courtney, 13 

Masting and Rigging, Kipping, 

21 
Materials, Campin, 18 

(Strength of), Barlow, 18 

Handling of, Zimmer, 1 

Mathematical Insts., Heather, 

55 

Heather &° Walmisley, 55 

Tables, Law and Young, 

22, 53 
Mathematics, Campin, 53 
Measures, Weights, &c, Wool- 
house, 56 
Measuring Builders' Work, 
Dobson and Tarn, 33 

Timber, &c, Horton, 33 

Meat Production, Ewart, 50 
Mechanical Dentistry, Hunter, 

45 
Engineering, Campin, 9 

Handling of Material, 

Zimmer, 1 

Terms, Lockwood, 8 

Mechanics, Hughes, 9 

Lardner and Loewy, 40 

Tomlinson, 10 

— — of Air Machinery, Weis- 

bach, 9, 22 
— (Tables for), Smith, 8 



Mechanics' Companion, Tem- 
pleton and Hutton, 8 

Workshop, Hasluck, 48 

Mechanism, Baker, 10 
Mensuration & Gauging, Mant, 

41 
and Measuring, Baker, 

17 
Metal Turning, Hasluck, 48 
Metalliferous Minerals, Davies, 

24 
■ Mining Machinery, Davies, 

22 
Metric Tables, Dowling, 49 
Metrology, Jackson, 49 
Microscope, Van Heurck, 40 
Milk, Cheese, &c, Oliver, 50 
Milling Machines, Horner, 2 
Mine Drainage, Michell, 25 
Mines of the Rand, Denny, 22 
Mineral Surveyor, Lintern, 27 
Mineralogy, Ramsay, 27 
Miners' Handbook, Milne, 25 

Pocket Book, Power, 24 

Mining, British, Hunt, 24 
Calculations, O'Donahue, 

26 

Chemistry of, Byrom, 26 

Students, Notes for, Meri- 

vale, 26 

Tools, Morgans, 27 

and Quarrying, Collins, 

27 
Model Engineer, Hasluck, 48 
Mollusca, Woodward, 40 
Motor Cars, Tayler, n, 47 

Vehicles, Tayler, 1 1 

Museum of Science and Art, 

Lardner, 41 
Music, Spencer, 56 

Natural Philosophy, Tomlinson, 

56 

■ for Schools, Lardner, 

41 
Naval Architect's Pocket Book, 
Mackrow, 20 

Architecture, Peake, 2 1 

Navigation, Young, 22 



62 



INDEX TO CATALOGUE. 



Navigation, Greenwood and 

Rosser, 21 
Practical, 21 

Oil Fields of Russia, Thompson, 
22, 41 
Oils, Analysis of, Wright, 41 
Optical Instruments, Heather, 

55 
Optics, Lardner cV= Harding, 41 
Organ Building, Dickson, 47 

Packing Case Tables, Richard- 
son, 38 
Painting, Qullick &° Timbs, 40 
Paper, Parkinson, 43 

Making, Clapperton, 43 

Watt, 43 

Pastrycook's Guide, Wells, 46 
Patents, Hardingham, 56 
Pattern Making, Hasluck, 48 

Horner, 8 

Perspective, Ferguson, 33 

Pywe, 34 

Pianoforte, Spencer, 56 
Pioneer Engineering, Dobson, 

15 
Plastering, Kemp, 33 
Plating & Boilermaking, .Hor- 
ner, 4 
Plumbing, Buchan, 33 
Pneumatics, Tomlinson, 19 
Pocketbook, Agriculturist's, 
Francis, 55 

■ McConnell, 52 

■ Builder's, Beaton, 33 

■ Electrical, Kempe, 30 

Engineer's, Clark, 7 

Edwards, 8 

Fletcher, 8 

■ Hasluck, 9 

Kempe, 7 

Smith, 8 

Templeton, 8 

Engineman's, Reynolds, 6 

Gas Engineer's, O'Connor, 

43 
— Health Officer's, Willoughby, 

35 



Pocketbook, Marine Engineer's, 

Mackrow, 20 

Wannan, 20 

of Mensuration and 

Measuring, Mant, 41 

■ Miner's, Milne, 25 

Power, 24 

— — Mining Prospecto r's, 

Anderson, 24 

— Merritt, 24 

■ Rankin, 23 

■ of Refrigeration, Tayler, 

10 
Portable Engine, Wansbrough, 

5 
Portland Cement, .Fai;a and 

Butler, 33 
Portuguese Dictionary, Elwes, 
56 

Grammar, Elwes, 56 

Producer-Gas Plants, MatJwt, 6 
Prospector's Handbook, Ander- 
son, 24 
Pumps and Pumping, 5a/e, 10 

Quantities (Builders'), Beaton, 33 

Railway Brakes, Reynolds, 6 

Working, Stretton, 19 

Reclamation of Land, Beazeley, 

12 

Refrigerating Machinery, Tay- 

ler, 11 
Refrigeration, Tayler, 10 

(Pocket Book), Tayler, 1 1 

River Bars, Mann, 14 
Roads and Streets, Law, 16 
Roof Carpentry, Collings, 37 
Roofs, Construction of, Tarn, 
iS 
Rothamsted Experiments, 

Tipper, 50 

Sailmaking, Kipping, 21 

Sadler, 21 

Sanitary Work, Slagg, 36 
Savouries and Sweets, Allen, 
47 



INDEX TO CATALOGUE. 



63 



Saw Mills, Bale, 36 
Screw Threads, Hasluck, 9 
Sea Terms, Pirrie, 21 
Sewage, Irrigation, Bum, 52 

Purification, Barwise, 36 

Sewing Machinery, Urquhart, 

47 
Sheep (The), Spooner, 50 
Sheet-Metal Work, Crane, 46 

Work, Warn &° Horner, 

46 
Shoring, Blagrove, 32 
Ship Building, Sommerfeldt, 21 

German, Felskowski, 21 

Ships and Boats, Bland, 21 
Silver, Metallurgy of, Eissler, 24 
Silversmith's Handbook, Gee, 45 
Slate Quarrying, Davies, 27 
Slide Rule, Hoare, 53 
Smithy and Forge, Crane, 9 
Soap Making, Watt, 44 
Soils, Bum, 50 
Spanish Dictionary, Elwes, 56 

Grammar, Elwes, 56 

Specifications, Bartholomew, 31 

in Detail, Macey, 31 

Star Groups, Gore, 40 
Statics, Graham, 17 

and Dynamics, Baker, 55 

Stationary Engine Driving, 
Reynolds, 6 

Steam Engines, Hurst, 6 

Steam and Machinery Manage- 
ment, Bale, 7 

and Steam Engine, Clark, 

10 
Steam Boiler Construction, Hut- 
ton, 3 

■ Boilers, Armstrong, 5 

Wilson, 4 

Engine, Baker, 6 

Goodeve, 5 

Haeder and Powles, 5 

Lardner, 6 

Safe Use of, 7 

Stone Working Machinery, 

Bale, n 
Strains in Girders, Humber, 17 
on Ironwork, Shields, 17 



Submarine Telegraphs, Bright, 

3° 
Superficial Measuremnt, 

Hawkings, 38 
Survey Practice, Jackson, 14 
Surveying, Baker and Dixon, 14 

Frome and Warren, 15 

Instruments, Heather, 55 

Land & Marine, Haskoll, 14 

Subterraneous, Fenwick, 27 

Usill, 14 

Whitelaw, 14 

with Tacheometer, Ken- 
nedy, 14 

Tea Machinery, Tayler, 46 
Technical Guide, Beaton, 33 

Terms, Fletcher, 8 

Timber Importer, Grandy, 37 

Merchant, Dowsing, 37 

Richardson, 38 

Toothed Gearing, Homer, 9 
Tramways, Clark, 16 
Transmission by Electricity, 

Atkinson, 29 
Traverse Tables, Lintem, 27 
Tree Planter, Wood, 53 

Pruner, Wood, 53 

Trigonometry, Plane, Hann, 55 

■ Spherical, Hann, 55 

Trusses, Griffiths, 18 
Tunnelling, Prelini and Hill, 15 

Simms and Clark, 15 

Tunnel Shafts, Buck, 16 
Turning, Engineers', Horner, 2 

Lathe, Hasluck, 9 

Metal, Hasluck, 48 

Wood, Hasluck, 48 

Ventilation of Buildings, Buchan, 

36 
Villa Architecture, Wickes, 34 
Visible Universe, Gore, 40 
Vitruvius' Architecture, Gwilt, 

35 
Watch Jobbing, Hasluck, 48 

Maker, Saunier, 44 

Repairing, Garrard, 44 

Watches, History of, Kendal, 45 



6 4 



INDEX TO CATALOGUE. 



Water Purification, Rideal, 35 

■ Engineering, Slagg, 13, 35 

■ Power of, Glynn, 13 

Supply, Humber, 12, 35 

Greenwell and Curry, 

12,35 
Supply of Towns, Burton, 

"> 35 
Waterworks, Hughes, 13 
Well-Sinking, Swindell, 13 



Wireless Telegraphy, Sewall, 29 
Wood Carving for Amateurs, 40 

Engraving, Brown, 47 

Turning, Hasluck, 48 

Woods and Marbles, Imitation 

of, Van der Burg, 38 
Woodworking, Hasluck, 48 

Machinery, Bale, 36 

Workshop Practice, Winlon, 9 
Works' Manager, Hutton, 3 




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